The Hitchhiker's Guide to the Galaxy is a franchise of different media, all telling variations on the same story by Douglas Adams.To boil it down to the essentials, Arthur Dent, a fairly normal if feckless Earthling, wakes up one Thursday and, after a series of confusing events, is spirited away from Earth by his friend, Ford Prefect, right before the planet is destroyed. He then hooks up with Zaphod Beeblebrox, former President of the Galaxy, current fugitive, and all-around cool guy; Marvin the Paranoid Android, a sarcastic and chronically depressed AI; and Tricia McMillian, AKA Trillian, The Chick and the only other human being left. Zaphod is on a quest to find The Truth, and everyone else gets pulled along for the ride.It's a sci-fi comedy with a special kind of absurdity that you're unlikely to find anywhere else.There have been many adaptations over the years, each one starting from this point and then branching off in a different direction. Adams himself was part of most of these, and thus, they all have some level of "officialness." It's not so much an Expanded Universe as a string of multi-media Alternate Continuities.The first version was the radio series, The Hitchhiker's Guide to the Galaxy. The first series was broadcast on BBC Radio in 1978, with another series coming not long after, and a Christmas episode linking them. This material went on to become the foundation of the first two books. However, it has several bits not seen in any later version, including the full-length "Shoe Event Horizon" story. After Adams's death, three more series were broadcast, adapting the plots of the last three books.Next came the book series, The Hitchhiker's Guide to the Galaxy, probably the best-known version. Originally, it adapted the plots from the radio series, but took off afterwards, becoming five novels in all. The third book was entirely based on a rejected story idea for Doctor Who, and one canon short story about Ronald Reagan was separately published without the name "Reagan" in it and made no sense as a result. The novels vary widely in tone and subject matter, and Mostly Harmless in particular didn't seem to please anyone, even its own author. Adams said near the end of his life that he wanted to do a sixth book which might round things out more nicely, but this was cut short by his sudden death. Specifically, he was believed to have been retooling an in-progress Dirk Gently novel into a new Hitchhiker's story; a few reconstructed chapters were published as part of the Salmon Of Doubt anthology book. A sixth book by Eoin Colfer, entitled And Another Thing... (not to be confused by a character dispensing important info just as they're about to leave) was published on October 12, 2009.The books, in order, are:
A six-episode TV series version was shown on The BBC, The Hitchhiker's Guide to the Galaxy. This, too, was based on the first radio series, and used much of its cast. It was innovative, particularly in its use of pen-and-ink animation to simulate the "electronic" entries of the titular Guide, but suffered from low budgets.There was an Interactive Fiction game, The Hitchhiker's Guide to the Galaxy, that was also largely written by Adams. It's known for being fiendishly difficult, yet a classic of the genre. A fully playable Java version of the original exists on Adams' own website, and can be found here, while the BBC website has two different illustrated 20th Anniversary Editions available on their website, here. The games have less plot than any of the other tellings, ending when you first set foot on Magrathea. A sequel was planned but never made.In 2005, a big-budget Hollywood movie version, The Hitchhiker's Guide to the Galaxy, came out. The script was based on a previous Adams-written script, and contained several new ideas by him, including the POV Ray and the Vogon homeworld. Reviews were mixed, with some appreciating the wit and ideas, while others grumbled at the lack of a real narrative backbone and slightly lethargic pacing.The series has also been adapted into stage shows (which made a lot of critics very angry and had been widely regarded as a bad move), albums, comic books, and even a version printed on a towel. There is also a website, created by Adams himself and originally run by the BBC, called H2G2.It now has a character sheet.
Tropes found in The Whole Sort of General Mish-Mash include:
Absolute Xenophobe: The Krikkiters, who on becoming aware that there was a universe outside their dust cloud decided that it all had to go.
Achievements in Ignorance: Invoked. To fly, one must aim at the ground and miss. To miss you have to distract yourself at the last moment. Then once you've achieved flight, you have to avoid thinking about how this is impossible or gravity will notice you, hard.
The Mice aliens in that they commissioned the Earth to be built (long story), and the dolphins are aliens in that they left the planet before it was destroyed. They even left a laser engraved fishbowl that gave us the title of the fourth book as a parting gift.
Alien Geometries: The inside of Wonko the Sane's house, "Outside the Asylum"; in the novels, Arthur valiantly tries to work out how the inside-out house actually goes together, but it never quite looks right to him.
Alphabet Architecture: The head-offices of the publishers who make the eponymous guidebook is shaped like a capital H, although why its shaped like this and not some alien lettering is never explained, but could be down to just another universal coincidence.
The official stance by fans is that the franchise has no canon, only suggestions. Each of the various formats the franchise covers (radio, novels, TV series, game, movie, etc.) directly contradicts all the others.
Played with in the radio series: "Many stories are told of Zaphod Beeblebrox's journey to the Frogstar. Ten percent of them are ninety-five percent true, fourteen percent of them are sixty-five percent true, thirty-five percent of them are only five percent true, and all the rest of them are told by Zaphod Beeblebrox".
The Alternet: The eponymous Guide updates itself over the "sub-ether," implied to be a galactic Internet-like communications medium.
Ambiguously Human: Almost every alien in the series, since Adams wasn't big on description.
Averted for the Vogons, despite the scarcity of the description, which includes a 'high domed nose' and a brain that turns out to be a misplaced, malformed, and dyspeptic liver.
The Artifact: Zaphod, at least if his absence in the last two Hitchhiker's novels Adams wrote is any guide; either Adams grew weary of the character or simply found him too difficult to write for. Every subsequent adaptation, including the radio versions made after Adams died has restored him to prominence.
Author Existence Failure: Trope Namer, almost; the third book mentions a "total existence failure". Later, of course, succumbed to the trope when Adams died while working on the sixth book; his last published collection of pieces, The Salmon of Doubt, contains an early draft of a Dirk Gently novel that Adams was hoping to rework into a Hitchhiker book.
Bad-Guy Bar: The Old Pink Dog used to have a sign that read "Please don't ask for credit because having your throat torn out by a savage bird while a disembodied hand smashes your head against the bar often offends". The bar's reputation eventually made the sign unnecessary.
Barred from the Afterlife: Arthur Dent mentions that he used to have a recurring nightmare where he died and there was a bureaucratic error: all his friends went to heaven or hell, but Arthur got sent to Southend.
Bathos: Used constantly for surreal humor. The page quote is just one of many, many examples.
Batman Gambit: In ''Life, The Universe and Everything Hactar takes advantage of his apparent failure to trick the people of Krikkit into destroying the universe to instead plant the real supernova bomb on Arthur and manipulate him into nearly doing so.
Big Little Man: The G'Gugvuntt and Vl'hurg, who spend thousands of years sending their fleet across space to attack Earth, only to be swallowed by a small dog.
Blessed with Suck / Cursed with Awesome: Marvin the Paranoid Android embodies both. He's a robot who exists entirely in a state of near suicidal depression, so being Nigh Invulnerable must be a horrible burden. Marvin's principal curse is that he was granted a "people personality" together with an almost limitless level of intelligence. While this may seem great on paper, it in effect meant that no task he could conceivably be given (including, at one point, solving "all of the major mathematical, physical, chemical, biological, sociological, philosophical, etymological, meteorological and psychological problems of the Universe except his own, three times over") could possibly give him any form of satisfaction. It's just one more example of the myriad ways the universe keeps kicking him in the plums. If robots have plums of course.
Give him the POV Gun and he can make a small army of Vogons collapse from depression, unable to fight. Of course, that will not make Marvin himself feel any more significant.
He does the same thing to the Krikkit robots in Life, The Universe, and Everything when the Masters of Krikkit salvage him and put his massive intellect to work coordinating their military strategy. The result was war robots who would go off and sulk and start doing quadratic equations instead of their job.
They harnessed Marvin's immense intellect to the Central Intelligence Core of the Krikkit War Computer. He didn't enjoy it. And neither did the Central Intelligence Core of the Krikkit War Computer.
And earlier in the series he drives an AI to suicide just by trying to talk to it.
Although in the book it says he shared his life view with it which, based on what we know of him, might be disturbingly convincing.
Brick Joke: It is revealed after missiles are launched that the only damage to come to anyone are 2 mice being freed and a bruised arm. The episode proceeds. The End Credits stinger? "I'm sorry, but I'd probably be able to cope better, if I hadn't bruised my arm."
The TV series used "Arthur bruised his upper arm" said by the narrator/book after all the credits had run. (Also, if you replay the scene and look carefully, you can see the fall that caused the bruise).
The LP record puts the End Credits stinger Arthur Bruised His Upper Arm in the run-out groove to the label, much like the famous backwards-talking line on the Beatles' Sergeant Pepper (a Shout-Out?)
It is quickly revealed that the fact of the freed mice is actually quite important.
Also, the third and fourth novel each retroactively create brick jokes out of what had originally been intended as unexplained throwaway lines: the third novel reveals the truth about the bowl of petunias that thought "Oh no, not again!", and the fourth re-introduces the girl from the cafe in Rickmansworth who was mentioned way back at the beginning of the series.
Not to mention the aside about living mattresses toward the beginning of the first book; eventually in Life, the Universe, and Everything we finally see one alive.
At the beginning of the game version, the player can pick up a toothbrush, upon which a tree falls on the phone lines. The game mentions that there is no causal relationship between these events. At the very end of the game, as the stinger, the game mentions that there actually is a causal relationship between these two events, and apologizes for the inconvenience.
In the secondary phase of the radio series, Arthur asks Ford "Who would want a motorised rock?" The response is essentially the same as Marvin's, to Zaphod's earlier question "Who in the Galaxy would want to bomb a publishing company?" (Another motorised rock/publishing company.)
The towel's role of importance to galactic hitchhikers, which was used in the TV series and the novelisation, was first used in the first chapter (or "fit") of the secondary phase.
Butt Monkey: Marvin on a lot of occasions has good reason for being so depressed. Most of the rest of the cast get to carry the Butt Monkey ball from time to time as well.
The Cast Showoff: Marvin (Stephen Moore) released four songs in the U.K.—"Marvin," "Metal Man," "Marvin, I Love You" and "Reasons To Be Miserable."
Marvin: "Life! Don't talk to me about life!" "Brain the size of a planet" "This terrible pain in all the diodes down my left side", and perhaps most famously, "I think you ought to know, I'm feeling very depressed"
Arthur: "So this is it. We're going to die."
Which is usually followed up after its first usage in a work by the Guide explaining Ford Prefect's theories on human speech and their tendency to state the obvious, the first being "If they don't keep talking their mouths seize up" and the second being "If they don't keep talking their brains start working", and then informing us that Ford quite likes humans even if the second theory is true.
Narrator/The Guide: "The Hitchhiker's Guide to the Galaxy has this to say on the subject of ____. It says that ____ is...", "By a startling coincidence"
City of Weirdos: Periodically played for laughs, most notably when the Guide advises aliens visiting Earth to land in New York, since it requires no effort to fit in.
Cool Starship: The Heart of Gold, the Starship Bistromath and several others.
Corrupt Corporate Executive The executives of insurance companies are implied to be this in general, since Trillian mentions that the death penalty has been instated for them, and when Arthur asks for which offense she merely responds "What do you mean, offense?"
Comes up on other occasions as well: for instance, the bright boys whose company produces a cloning machine that you essentially can't turn off without committing murder simply have their legal department write up a series of Agreements to Cease to Be. Clever, yes, but quite soulless.
Corrupt Politician: Played for laughs. Many galactic presidents are arrested on election, on general principle.
The essential dilemma of elective politics is summarized in the second book: "Anyone capable of getting themselves elected President of the Galaxy ought on no account to be allowed to do the job."
Zaphod is mentioned as being one of the most successful Presidents the Galaxy has ever had, having already spent two years of his ten year term in prison for fraud.
Creator Breakdown: Regarding the Downer Ending of Mostly Harmless and the mixed-to-negative reaction from fans, Adams conceded, "I just had a thoroughly miserable year, and I was trying to write a book against that background." He intended a sixth book to give the series a better conclusion, but succumbed to Author Existence Failure first.
Cross Cultural Kerfuffle: A minor, comical example. During the section explaining how scientists view of the Babel Fish has allowed for the final proof of the non-existence of God, it is said how one can then go on to prove black is white and promptly get run over at the next zebra crossing. In Britain and many other countries, black-and-white stripped "Zebra Crossings" are the equivalent of the (often yellow or parallel lined) American "Crosswalk". Americans, when reading the joke, usually imagine the term as an equivalent to a "Deer Crossing" (that is to say, a place where zebras cross) which makes for an equally humorous, though widely different joke.
There's an in-story example, where a casual throwaway remark Arthur makes regarding his lifestyle leads to an interstellar war of gargantuan proportions note from the perspective of the participants; both sides ultimately invade Earth and their forces are swallowed by a small dog breaking out.
The Ford Prefect was a small car Ford designed and manufactured in England, sold in America only in tiny numbers as a specialty import and unknown to all but car-trivia buffs by the '70s. Adams regularly commented on how Americans were completely unaware of a joke they weren't getting.
Other countries that did translate it had to find ways of getting around the problem. Usually by renaming him "Ford Escort".
The TV series downplays it by showing a list of names Ford considered using, most of the rest being much more recognizable, at least getting across the impression that he's named after something real. The movie lampshades it by Ford referring to Arthur meeting him by saving him from being run over when he tried to shake hands with a car (which he now explains, having revealed himself to be an alien, he had mistaken for the dominant life form on Earth).
Cosmologist Carl Sagan once speculated that any alien observing Earth from orbit would come to the conclusion that the dominant life-form has wheels. Human beings are their lesser symbionts who do everything for their wheeled masters, cleaning them, feding them, maintaining them, and at great time and labour, constructing their massive migration pathways and rendering their going smooth. The whole thing about the Ford Prefect is homage to Sagan.
Data Pad: The Guide itself is like a dedicated e-book reader, seeing as if it were put on paper it would take up several large buildings.
Deus ex Machina: The ending of the radio series. Arthur and the other main characters are spared from the destruction of Earth by the implanted Babel Fish, who are revealed to be relatives of dolphins, and transplanted to the Restaurant at the End of the Universe. It is also revealed that beyond the Restaurant lies an endless series of blue lagoons, which is the final destination of the dolphins. Arthur asks Fenchurch, "Will you come flying with me?" She responds, "Always". A lot of fans prefer it to the much darker ending of Mostly Harmless.
On one occasion the argument is put forth that Disaster Area is actually good for the environment, on the basis that a show in a desert causes the entire desert to fly into the air and flip over like a mile-thick pancake, and the resulting exposure of fertile soil causes a field of vibrant flowers to sprout in short order.
Also Disaster Area is the only noise in the universe loud enough to drown out the unwanted telepathy of the above-mentioned Belcerebons - this is why the Disaster Area concert takes place on Kakrafoon. The Belcerebons are quite lucky - since Disaster Area is established as the loudest noise in the universe, it not being loud enough would mean there is no cure at all.
An odd example of this trope. While the Earth is important to the mices' plans, what are those plans? To go on the talk show circuit and get rich. The only version of the Ultimate Question we learn is nonsense. When another character learned universal Truth by another method, it drives some people mad, but has more to do with frogs than universal epiphanies and isn't mentioned again in any of the following books. There is a Ruler of the Universe, and he doesn't live on Earth. All things considered, Earth is more important to the universe in this series than it seems in Real Life, but it's still an absurd, farcical, nearly crapsack universe full of Shaggy Dog Stories, so nothing is all that important.
Executive Meddling: In Life, the Universe, and Everything, the Silver Bail of Peace is the Rory Award for "Most Gratuitous Use of the Word 'Fuck' in a Serious Screenplay". US censors were offended, and Adams, bowing to their wishes, promptly changed the offending word to "Belgium". Subverted in that the resulting passage was much funnier, as Adams modified the surrounding conversation to fit the change, as well.
Famous Ancestor: Mr. Prosser is, humorously, a direct descendant of Genghis Khan. And Another Thing adds another that is the descendant of the Norse hero Sigurd. Needless to say, he becomes obsessed with Thor once he lands on Nano.
Fantastic Racism: In the radio series, the shape-shifting Haggunenons hate all the "filthy rotten samelings".
Then there are the Krikkiters in LIFE, THE UNIVERSE AND EVERYTHING, who wanted to destroy ALL other life forms. (But it turns out they were being manipulated by Hactar.)
Faster-Than-Light Travel: First hyperspace which was unpleasant and occasionally erased people from existence or otherwise when horribly wrong. (Mostly in the fifth book). The infinity improbability drive which kept turning planets into cake and finally a bistro mathematics powered drive.
Fiction 500: The "plutonium rock band from Gagrakacka Mind Zones," Disaster Area; and Magrathea, the planet that became so rich the rest of the galaxy's economy collapsed.
Fictional Colour: Hooloovoo is a supersmart shade of blue. And by "supersmart", we mean "sentient and intelligent."
The part on Bartledan literature is foreshadowing on the use of foreshadowing in Mostly Harmless. In the book Arthur reads, the main character dies of thirst just before the last chapter, because of some problem with the plumbing that is only referenced once at the beginning of the book. Arthur finds this exasperating. Of course, the few clues that explain the Bolivian Army Ending are hidden the same way in Mostly Harmless. The reader finds this exasperating.
The demolition of Arthur's house due to a huge bureaucratic cockup foreshadows Earth's fate.
Although it is subverted in the books and the movie by The Reveal that it was actually malicious. (For money in the books, and to break up Zaphod and Trillian in the movie.)
Friendly Playful Dolphins: This trope is stated to be why dolphins are a Superior Species — while humans went around having wars and inventing the wheel, dolphins just splashed about in the water having a good time. Their final message to humanity ("So long, and thanks for all the fish") was disguised as "a sophisticated attempt to jump through a hoop while whistling The Star-Spangled Banner."
Genesis Effect: The Magratheans create customized planets for very wealthy customers.
Genetic Memory: Humans created Cricket out of a racial memory for the Krikkit wars.
Genocide Backfire: The Vogons may be too stupid and apathetic to care, but they destroyed a five billion year old supercomputer (Earth) just as it was finishing its calculations of, basically, the ultimate meaning of everything.
Genre Shift: While remaining comedic first and foremost, the first two books are picaresques, the third is a caper, the fourth a romance and the fifth almost hard sci-fi.
His final message to His creation is "We apologise for the inconvenience."
One of the first things mentioned in the books and miniseries is the blockbuster philosophical trilogy "Where God Went Wrong", "Some More of God's Greatest Mistakes", and "Who Is This God Person Anyway?"
The author of these books was Oolon Coluphid, who went on to write "Well, That About Wraps It Up For God" when it was shown that the Babel Fish proved by its sole existence by chance that God does not exist. However, it is noted that most theologians consider this a load of dingoes' kidneys.
Godly Sidestep: The Answer doesn't mean anything. The Question (which ought to clarify matters) is never seen in its completed form, as the Earth blows up five minutes too soon.
Several versions of the story mention that it has been theorized that if anyone were to learn both the Answer and the Question so that it makes sense, the universe will promptly disappear and be replaced with something that makes even less sense. (A corollary to this theory states that this has already happened at least once.)
The footnotes of the original radio scripts notes that a letter in The New Scientist points out that 42 is the atomic number for Molybdenum, a chemical thought to have been instrumental in the creation of organic life.
Good Guy Bar: Milliways, the Restaurant at the End of the Universe. It's also implied that the Big Bang Burger Bar at the other "end" of the universe is one as well.
It involves throwing yourself at the ground and missing. This can only be accomplished by distracting yourself from the fact that you're about to hit the ground, thus inverting Dogbert's approach on Gravity Is Only a Theory.
In this case the poor unfortunate gazelle-like creatures are used more as furniture than transport, as they were too fragile to support a full-grown Vogon and their backs would snap instantly under the strain.
Humans Are Morons: Arthur Dent, the only human left alive (except for Trillian), is constantly being referred to as an ape or otherwise put down as a moron (mainly by Zaphod, though he isn't exactly bright himself.)
Hyperspace Is a Scary Place: Travel through hyperspace is described as "unpleasantly like being drunk." "What's so unpleasant about being drunk", you say? Ask a glass of water.
The Infinite: As a speed you can move at it is played for all the absurdity it is worth with the Infinite Improbability Drive. Where you can move at infinite speeds but only if the destination is really improbable.
Its certainly viewed as this for the most part. The in universe Hitchhikers Guide, which has an entire chapter devoted to towels, has a two word entry for Earth "Mostly Harmless" and this is an update after a decade of research, the previous entry was simply "Harmless."
For instance, a giant cup made out of solid marble being held up fifteen miles in the air by art.
The Bistromathic Drive is far more efficient than all that mucking about in hyperspace or Improbability Factors because it runs off a form of mathematics based off the calculation of restaurant bills.
Hey, when you break the laws of physics everything becomes absurdly simple nonsense. It's how bistros stay in business, so why can't we do the same for Casual Interstellar Travel?
The Bistromathics Drive is probably similar to how Earth is-was the greatest supercomputer in the history in the universe albeit on a smaller scale.
At one point in history, someone built a space ship powered by bad news, because as everyone knows nothing travels faster than bad news. Unfortunately, when it arrived at its destination, nobody wanted it.
Then there's the literally flying party...
Well, the partygoers were drunk and had the expertise to make the building do so.
And, as the book points out, the problem with a party that never ends is that all those things that only seem like good ideas at parties keep on seeming like good ideas...
It's A Small World After All: Arthur is the only man to escape Earth before it's destroyed, and who should he run into almost immediately, in all the galaxy, than the only woman to escape Earth, and it turned out to be someone he'd met. Of course, this was due to the intervention of a spaceship powered by improbability, and the ship computer even suggests it's all interconnected.
Large Ham: In most versions featuring audio of some sort, Zaphod is often played as a fresh large ham.
The print version pretty much portray Zaphod this way as well. It's even more obvious when you know that when Douglas Adams wrote the original radio play, he based the character of Zaphod on similar characters played by actor Mark Wing-Davey, who played Zaphod in the radio show and television series. Large Ham is a quintessential part of Zaphod's nature.
Valentine Dyall's portrayal Deep Thought. A multi dimensional super-computer is able to take hamminess to levels that are not normally physically possible.
Law of Conservation of Detail : Subverted to hell and back, probably deliberately. The narrative throws in references to bizarre alien places and things via the Guide frequently. A few of them pop up later in the same book or radio show, a few of them become Brick Jokes when a later book or show makes a Call Back to them, and some quite clearly were random jokes that no one ever fleshed out or ever intended to.
A whole chapter in the fourth book is dedicated to Adams explaining this concept to the readers, stating it is the reason why he doesn't go into all the details of Arthur Dent's life, and why he sometimes omits entire periods of time.
Life Imitates Art: Smartphones and tablets with access to Wikipedia mimic the capability and functions of the Guide with uncanny accuracy.
Living Legend: The Guide notes that towels (in addition to several legitimate uses) let you cultivate this image. If you can hitch the length and breadth of the galaxy and still know where your towel is, then obviously you're a Bad Ass, and others will think nothing of loaning you some other minor item that you happened to recently misplace.
Mechanistic Alien Culture: The Vogons are not-so little Green Men whose overly bureaucratized society, like the Hierarchy in Star Trek: Voyager, may be taken as a parody or a deconstruction of this trope, with the over-bureaucratization standing in for over-mechanization.
Memory Gambit: Zaphod setting up a scheme to learn who the ruler of the universe is, which involved giving himself self-imposed amnesia so that he could become president, allowing him to steal a ship equipped with the Infinite Improbability Drive so that he could find the hidden planet used to hide the aforementioned Ruler of the Universe.
Mike Nelson, Destroyer of Worlds: The Vogons demolish populated planets for extremely petty and bureaucratic reasons, usually related to hyperspacial traffic-calming initiatives.
The entire population of the planet Krikket who are described as being charming, delightful, intelligent, whimsical homicidal maniacs. They almost wipe out the universe without realising that doing so would take them with it. The fact of the matter is that they're really just patsies for Hactar, the Omnicidal Maniac who is pulling their strings
Monkeys on a Typewriter: As a result of the Infinite Improbability Drive, Ford and Arthur get approached by "an infinite number of monkeys who want to talk to us about this script for Hamlet they've worked out."
Morning Routine: The opening, with Arthur Dent waking up as normal to discover his house is about to be bulldozed... and his planet destroyed.
Mr. Exposition: The Book, and to a less literal degree, Ford and Slartibartfast.
Multiboobage: Eccentrica Gallumbits, the Triple-Breasted Whore of Eroticon VI.
Mundane Made Awesome: In the fifth book, Arthur is practically worshiped as a god for his incredible skills at... making sandwiches.
Nobody Poops: Lampshaded in the new radio series adaptation of Life, The Universe, and Everything. "You know, in all this time I have never once ''flush''".
Nonindicative Name: Marvin is known as "The Paranoid Android," but he's not remotely paranoid. He's depressed, nihilistic, sarcastic, pessimistic, and a few other adjectives, but never paranoid.
Several people (including Marvin himself) refer to him as a "manically depressed robot". Whatever he is, he clearly doesn't suffer from manic depression (now formally known as "bipolar disorder"), which involves mood swings between manic and depressed extremes—we never see Marvin being manic. Of course, "manically depressed" isn't a medical term; perhaps it just means "enthusiastically, whole-heartedly depressed", which he is.
Noodle Implements: Twice in the book series: Wowbagger the Infinitely Prolonged became that way due to an accident involving a particle accelerator, a liquid lunch, and a pair of rubber bands. The other was due to an incident with a time machine and a contraceptive, maybe
The second one is the reason that Zaphod's direct ancestors are named in reverse order; his father is Zaphod Beeblebrox the Second, his grandfather the Third, and so forth, all the way back to Zipo Bibrok 5 × 10 to the 8th power or some damn thing.
Fenchurch's discarded underwear were also noodle implements in their own right as they massively changed lives for reasons not gone into.
The Nudifier: Finite improbability generators were doing this in their early versions.
Older than They Look: Early in the first installment, it's revealed that Zaphod Beeblebrox is about 200 years old, which means also that Ford Prefect is as well, since they were childhood friends. It's only mentioned in passing, though, and doesn't really matter much to the plot.
Only Known by Their Nickname: The name Ford Prefect was born with is long since lost in the mists of time. Apparently he couldn't pronounce his own given name, causing his father to die of shame. Before he adopted the Ford Prefect moniker, he was known by the nickname Ix.
Only Sane Man: After being convinced the entire universe is insane, Wonko the Sane built an inside-out house and named it "Outside the Asylum". If the outside of the house is on the "inside", then everything on the outside is also on the "inside" and thus safely contained. (If you know topology, this makes absolutely perfect sense — see, he told you he was sane.)
Outsourcing Fate: To the real President of the Galaxy, a little old man in a shed in the middle of nowhere. All he's interested in is feeding his cat, but occasionally people stop round and ask him what he thinks about certain things.
Promoted to Love Interest: Trillian in the movie. In the novels, the relationship between Trillian and Arthur is somewhat schizoid — Arthur had a chance with her at one point before she became involved with Zaphod, but they get Ship Teased in Life, the Universe, and Everything, get sunk in So Long and Thanks For All the Fish when Arthur hooks up with Fenchurch, and actually have a daughter together (via sperm bank) in Mostly Harmless.
Put on a Bus: Fenchurch after So Long, and Thanks for All the Fish
Reality Breaking Paradox: The second book states a theory which basically says that if anyone finds out the meaning of life, then the universe will end and reboot as something even harder to explain. (Another theory says that this may have happened.) Life, The Universe, And Everything later handwaves away The Ultimate Question and Answer Of Life, The Universe, And Everything as causing such an event if anyone found out both.
Relatively Flimsy Excuse: The radio series has a subversion of the 'this autograph isn't for me' variant: "It's not for my daughter, you understand, it's for me." (It turns out to be a ruse to get Zaphod's signature on a contract he'd never have signed voluntarily.)
Riddle for the Ages: The Ultimate Question to Life, the Universe and Everything, although there's a hint in Life, the Universe and Everything that it may be "Think of a number, any number."
Robot Buddy: Subverted with Marvin the Paranoid Android, and just about everything made by the Sirius Cybernetics Corporation.
Sanity Ball: Arthur starts off as the sane one. Ford quickly takes over this role. You know things have gotten weird when Zaphod gets the ball, however temporarily...
Sapient Cetaceans: In this series humans are stated to be actually only the third most intelligent creatures on Earth. The first is mice. But then, they are hyper-intelligent pan-dimensional beings who are actually running the Earth, which is a giant computer program, and the second is explicitly stated to be dolphins (who aren't in disguise and are still ahead of humans), and who knew about the impending destruction of Earth long before the humans themselves knew about it. The dolphins tried to warn them, but when the humans didn't understand, they left the planet quietly by their own means. Their last message is "so long and thanks for all the fish", and this all becomes important in the book So Long and Thanks for All the Fish. At the end of So Long and Thanks for All the Fish, it's all but stated outright that the Dolphins were responsible for restoring Earth.
The Movie even gave the dolphins a musical number as an opener, complete with a beautiful view of them shooting into the skies like rockets.
Sapient Ship: The spaceship Heart Of Gold is maintained by Eddie, a Sirius Cybernetics Corporation computer with a sickeningly cheerful and optimistic programmed personality. Other equally unlikable computers have been installed to run other functions on the ship as well, right down to automated doors run by programs that live for the chance to open and close for someone. At one point Zaphod discovered that Eddie had an emergency backup personality - unfortunately, it was worse.
Sapient Tank: Marvin provokes a massive but simple-minded robot-tank that's standing on a bridge connecting two high office towers into showing off it's destructive arsenal, and the drone promptly shoots the bridge supports, resulting in it falling down and getting smashed.
On one side, one of his quotes in the first book is incredibly fitting and is even the page quote for Conveniently Close Planet: "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space..."
However on the other side of the scale is the fact that the characters speak of the galaxy they live in as being the be-all-end-all of everything... then they come out with the infinite improbability drive which goes through ...every point in the Universe simultaneously....
Silly Reason for War: The war between the G'Gugvuntts and Vl'hurgs is trigered by Arthur uttering "I seem to be having tremendous difficulty with my lifestyle" which in the Vl'hurg tongue is the most dreadful insult imaginable. The words bizarrely reached their ears and this left them no choice but to declare war on the G'Gugvuntts, which went on for a few thousand years and decimated their entire galaxy. They eventually learn the origin of the misunderstanding and join forces against the Milky Way but their invasion fleet is swallowed by a little dog.
The Slow Path: One of the ways in which the universe keeps kicking Marvin in the teeth is that he keeps getting sent back in time but never forward, resulting in him just waiting around to intersect with the rest of the cast again. By the end of his life he is more than 37 times older than the universe itself
Spanner in the Works: The aforementioned Gambit fails because Arthur is absolutely the worst cricket bowler ever.
Spared by the Adaptation: Pretty much all the main characters (yes, that includes Marvin) in the Radio adaptation of Mostly Harmless.
Spoiler: In-universe example, at the beginning of the missile attack, although this is done ostensibly in order to reduce suspense-induced stress (the narrator says so). It does preserve a minor piece of suspense, however, by not telling us exactly who's arm is bruised.
See also: Peril-Sensitive Sunglasses.
Spot of Tea: A recurring theme is Arthur's inability to get one.
The Infinite Improbablity Drive is created by putting an atomic vector plotter into a source of brownian motion, which happens to be a "nice hot cup of tea."
The Stinger: The reveal of the identity of the person who bruised their arm in the missile attack comes at the end of the radio and TV episode it occurs in, and the end of the chapter in the book.
Take That: Ever wondered why the worst poet in the universe was changed from Paul Neil Milne Johnstone in the radio series to Paula Nancy Millstone Jennings in all other versons? It's because Johnstone was a real poet who was at university with Adams; though "amused" at being called the worst poet in the universe, he objected to his address being broadcast (instead of "Beehive Court, Redbridge", Paula lived in "Wasp Villas, Greenbridge"). The snippet of Paula's poetry seen in the TV series ("The dead swans lay in the stagnant pool...") is a genuine poem that Johnstone wrote. Johnstone went on to be quite a successful poet, but he admitted that the stuff he wrote as a teenager sucked.
Talking the Monster to Death: Marvin does this by accident, by plugging himself into a ship's computer and telling it how depressed he is. This also kills two soldiers whose life support is connected to the computer.
He also talks a tank and a bridge to death.
Although the tank is a subversion, since he actually tricks it into sending itself plunging to its doom, rather than making it suicidally depressed. The bridge, however, appears to have been intentional.
It should be noted that the Guide itself doesn't even bother with the tenses, and simply mentions that they don't use the future perfect tense, because it was found not to be.
The text gives some examples of the usage of the entirely correct tenses, for about one paragraph, following mentioning the book by Dr. Streetmentioner, and stopping before the note about dropping the 'future perfect' tense.
Timey-Wimey Ball: since the whole Time Travel thing (and indeed pretty much every other sci-fi concept) is played for laughs, don't expect consistency. This is lampshaded and played with constantly.
Too Soon: An in-universe Too Soon: the sheer tastelessness of a genocidal war being reduced to an entertaining British ball game has caused most of the galaxy to shun humanity.
Also, The BBC provided a content warning when the episode involving the air attack on the Guide offices (a giant H-shaped skyscraper) was aired shortly after 9/11 - to their credit they didn't postpone the broadcast altogether.
Translation: Yes: Ford's former alias was "Ix", which means "Boy who is unable to satisfactorily explain what a Hrung is, or why it should collapse on Betelgeuse Seven".
Villain Decay: The Vogons suffered from this over the many iterations of the story. Although they're described by Word of God as "not actually evil", in the radio series they're malicious and vindictive Punch Clock Villains, taking definite satisfaction in throwing hitch-hikers out of an airlock to apparently certain death, and in the first five books they're even worse, obliterating every possible trace of the main characters from every alternate universe just to finish a demolition job. In the movie they're more like Big Bad Wannabes, opting not to track down the fleeing heroes because it's their lunch break. In the 6th novel, there's even a nice Vogon.
The Wall Around the World: Wonko the Sane constructs a wall around his home to fence in the world, which he calls "the Asylum."
Warrior Poet: The Vogons, in a depressingly literal fashion.