Any violation of continuity, logic, physics, or common sense is permissible if the result gets enough of a laugh.
This is the comedy equivalent of the Rule Of Cool, and is accordingly weighted more in comedy shows. Especially easy to invoke in humor-based American animation and webcomics, where people expect the lack of realism in the art to translate to other areas.
Compare Rule of Fun.
Tropes existing purely due to the Rule of Funny:
A running sight gag in Azumanga Daioh is Sakaki, after winning a race, running with the ribbon held up by her (for a Japanese teenager) extremely large breasts. Of course, this means that the ribbon was chest-level on the tallest girl, putting it high enough that some of the contestants would have run right under it...but it's still funny.
Sakaki generally bends down a little and kind of "scoops" the ribbon when she runs through. Although I didn't find it funny so much as mildly cool.
One Piece uses this for a number of things (some of which later get a Cerebus Retcon), but one to note is Franky building a nice-looking wooden bridge out of scraps and rubble in less than a minute. It would be a Deus ex Machina if Franky's insistence on the level of detail and craftmanship didn't make it hilarious.
For those who haven't seen the above scene, the bridge has carved, ornate hand rails. Oh and it was varnished.
Luffy eating a cage he was trapped in certainly qualifies, especially because he's captured again before he achieves anything. The whole scene serves no purpose but Rule of Funny.
Larry Elmore used this in his classic Snarfquest comics that appeared in Dragon Magazine, citing that his manner of plotting the episodes was to figure out the ending goal of the characters then throw out the plan and write/draw the stupidest possible way they could get there.
Don Rosa uses this trope from time to time as a justification for breaking realism in his otherwise painfully serious comics. He even mentions it (though not by name) in one of the comment pages for The Life and Times of Scrooge McDuck, when he had retroactively added the Eisner comic award◊ he won for the series in its last chapter, hanging on Scrooge's wall. Donald Duckeven remarks that it has to be fake, since they're living in the 50s and the award reads "1995" with big letters. Rosa compares his relationship with the rule to the below-mentioned joke in Roger Rabbit.
To wit, Dirk Anger, director of H.A.T.E., (A Nick Fury expy) spends the entire series a) trying to kill Nextwave by, say, throwing Drop Bears at them from his flying submarine base, and b) concocting ever more elaborate suicide attempts due to the breakdown the Nextwave squad are giving him.
Eddie: You mean you could have taken your hand out of that cuff at any time?! Roger: No, not at any time. Only when it was funny.
This being the most frequently referenced instance of the rule, it's interesting to note that, the way Roger Rabbit phrases it, you can never be quite sure if he isn't just pulling Eddie's chain. ...in the figurative sense.
The scene in Transformers where the Autobots hide in Sam's backyard doesn't make that much sense - why wouldn't Sam's parents hear them speaking? - but it's so damn funny it barely matters.
In Atlantis: The Lost Empire a chalk map that rubs off on Milo's shirt is not reversed, as the gag of Milo having to stand in that position would have been voided. The directors were amused that test audiences complained more about that detail and its plausibility than in the following scene where a photograph whirs into life in a 1920's movie style.
Certain comedy films can't go one minute without violating all sanity for a joke. Consider Top Secret!, featuring a very young Val Kilmer as a rock & roll star protagonist in a spy plot: this movie includes a motel called Gey Shluffen, a high speed action chase to change a radio station, and an underwater bar brawl. Or watch Airplane! for the sheer number of visual pun gags.
Woody Allen's early films were very much of this order. Consider Take the Money and Run where Woody is imprisoned and punished by being locked in confinement with an insurance salesman. Or Love and Death where a battle scene is intercut with scenes of Woody as a cheerleader.
Pavi Largo's accent in Repo! The Genetic Opera. He's the only one of his siblings with an Italian accent. It appears only to be there to make him hilarious. (It works.) *
the writers have subsequently stated that Pavi developed his accent to cover up a childhood speech impediment. But seeing as the film itself offers no such explanation, it probably still counts as Rule of Funny
"All of-a eet? OHHHH NOOOOOO!"
The Madagascar movies follow RoF to an increasing degree with every movie.
Every Marx Brothers film revolves around this, to a varying degree. Many of their best routines have absolutely nothing to do with the plot
The final scene of Casino Royale 1967 is so completely nonsensical that it's impossible to describe. Allegedly, the scene is the heroes trying to get out of the casino before it explodes. So why the cowboys, Indians, flying roulette table, bubbles, kinescope police dispatchment, gun-turret banister, etc.? It's funny...at least if you're high enough to write a scene like that.
The climactic battle of Blazing Saddles, which features the characters leaving their soundstage and breaking up a dance number on another set, getting into a pie fight in the studio commissary, then (eventually) getting to the end of the movie by sneaking into a theater playing Blazing Saddles and watching it with us.
Combined with Stylistic Suck for the Swedish action-comedy Kopps. A policeman is given ridiculous superpowers, that begin with him arriving at the scene of a robbery seconds after the alarm is activated, flipping his car in the air and landing perfectly on all four wheels, and then...all of this happens.
In the final scene of A Fish Called Wanda, Otto is seen hanging on to the window of an airplane taking off, having apparently survived being run over by a steamroller and smushed into wet cement. On the DVD, John Cleese argues that this joke wouldn't have worked at any point in the film other than the very end.
In the Discworld universe, this is an actual rule, akin to a law of physics. Terry Pratchett, author of the series, has cited this rule in interviews. GURPS Discworld (co-authored by Pratchett himself) elaborates that it is a corollary of the Law of Narrative Causality, known as the Rule of Universal Humour. That term appears once in the novels themselves, mentioned as the reason someone still had his hat on after being turned into a pumpkin.
Tom Holt and Robert Rankin have based their entire careers on this. With Holt, you know the book you're reading is based on the same plot as the last five books of his you read — and you don't care; with Rankin... well... the closest description anyone's ever found to his books is The Goon Showon crack, and this is pretty much the only rule it abides by.
Craig Shaw Gardner's "Cineverse Cycle," as a parody of B movies in general, pretty much lives and breathes this trope, whether it's the subtitles that appear underneath the inhabitants of the "foreign film" universe whenever they speak, or the mad scientist who turns into a Gargamel parody whenever he's around this bunch of fluffy bunnies in the "cartoon" universe, or the slime monster in the "horror" universe which turns out to be the formerly-missing chimp companion of the Tarzan-parody character in the "adventure" universe, clad in a monster suit.
Any "plot" elements in Mystery Science Theater 3000. See the mantra. For example, Season 7 ended with Dr. Forrester being reborn and then killed by Pearl, who then freezes herself. A later episode shows her and the cast go back to the present, so the second Dr. Forrester would still be around, if it had to make sense.
On the show Merlin during the episode "A Servant of Two Masters", Merlin continuously (and humorously) fails to kill Arthur by using weapons and chemicals.It is because of this trope the Merlin doesn't use magic to try and kill Arthur.
The title character of Angel could go from dead serious to goofball surprisingly fast.
In fact, the entire point of "Smile Time" seems to be this trope. There is a mysterious bad guy, it could do anything. Why would it turn Angel into a puppet? Because it's hilarious, that's why.
Actually, it's symbolic of the fact that Angel has been various people's puppets pretty much since the show began, and the purpose of the egg was to turn demons into puppets (so they could take over a kid's show)...
But, mostly, it's really, really funny.
Red Dwarf has briefly Flanderized Holly's senility for a joke multiple times, with the extreme being "White Hole" (in which (s)he was counting by banging her head on the screen). However, (s)he is shown to be much more lucid (if not necessarily brilliant) in other episodes, notably in "Queeg" with a well-planned hoax based on the idiot-perception and in "Back to Reality" when (s)he saves the entire crew. Also, "White Hole" itself establishes that the ship's power generation requires her input, making you wonder why something hasn't exploded yet.
Perhaps the flaw of the final two series where whole scenes seem to have been tacked on mainly for laughs. The most glaring are the tap dancing shuttle craft scene and the Tyrannosaurus rex, (of course) eating a giant curry. Pretty base stuff by the series previous standards and not helped by some not-very-convincing CGI.
There's a glorious piece in the script book, where Naylor describes, step by painstaking step, just how complex the dancing Blue Midget scene was to do, then going on the messageboards and learning "the fans hate it, they think it's filler".
Many of the "challenges" in Top Gear. Why turn a truck into an amphibious vehicle? Why launch a car on a rocket only to see it hit the ground and then explode? Why make James May try to drive fast? (Or why let him get lost—actually lost—on a race track? Because it's funny, durn it!)
On The George Burns and Gracie Allen Show, George made it clear in his occasional asides to the audience that he would go along with anything as long as it was getting laughs.
Pretty much one of the main reasons Adam as well as the Chuckleheads (Kari, Grant, and Tori) are around in MythBusters is because they all fulfill the Rule of Funny. Jamie and Adam admit they really aren't that fond of each other in real life - if it weren't for the Rule of Funny, you can bet your bottom it'd just be two Jamie type people.
The reason X-Play was very fond of finding a quote they thought was amusing, then repeating it. Again. And again. And AGAIN!
This is practically Hyde's excuse for his antics—"Because, it's funnier this way."
CHIKARA Pro Wrestling, Incredibly Strange Wrestling, and Lucha Va-Voom practically run on it.
Why does Bluebottle in The Goon Show keep getting deaded by explosions even when he's in the middle of a desert on a different continent to the pile of dynamite he's fleeing, then come Back from the Dead to complain about being killed? Because it's funny. The same applies to...well...pretty much everything else related to the Goons.
The election night newsreel in Of Thee I Sing relies heavily on the Rule of Funny. In particular, the actual opposition candidate is never identified, so all the election returns show Wintergreen vying with various celebrities, horses, intoxicating liquors, etc.
Philocomasium's Zany Scheme in Miles Gloriosus depends very heavily on this, as she's masquerading as her free twin, while the man whose concubine she is has a guard for her.
Conker. To explain, antics such as producing toilet paper from Hammerspace when fighting a giant singing poo, and drinking from a conveniently placed keg in order to defeat fire imps with "yellow rain". Or as the game puts it, the 'Context Sensitive Area'.
Mass Effect 2's infamous "probing Uranus" joke requires a deviation from format to execute. Normally, when the player deploys a probe, the ship AI will say something like "Probe away" or "Deploying Probe." It never, never says "Probing [Planet Name]"....except when you launch a probe at Uranus, at which point you hear "probing Uranus."
With enemies like giant hamburgers and chests of drawers and superpowers like "eating spicy foods without distress" or "folding roadmaps correctly," Superhero League Of Hoboken pretty much runs on this trope.
Bayonetta is a violent, bloody, crazy, and sexy game. But in Chapter 9, the eponymous witch can get flattened in cartoon fashion, which seems completely out-of-place in a game like this, but it's still funny, so that's all that matters.
Kusari: I'll be briefer [kills Schlock, turns to Daedalus] I've located and eliminated Dr. Schlock as you ordered, Daedalus.
Daedalus: I wanted to hear what he had to say, but that was pretty funny so you get a pass.
This very much governs Brat-Halla. It tends to hew surprisingly closely to accurate Norse mythology within the confines of its premise... except when it would be funnier not to. Thus, Tyr is a pacifist, Fenrir is a rock star, half the dark elves are poser goths and emo kids who hang around coffee shops, and the closest thing the comic has to a Big Bad is the eye Odin sacrificed to the Well of Mimir, imbued with sentience and severe abandonment issues.
In Jayden and Crusader this is referenced by a simple Saxon/Norse superstition being used in the 21st century, and turning out to be true for only the comic in which it is mentioned.
Later the Artist of J&C himself cited the Rule of Funny regarding his own work
In Girl Genius, Violetta is able to swap a hostage for a matching dummy of him, while the hostage is being physically held by his captor, while Violetta is physically separated from and arguing with said captor, with no explanation of where that dummy might possibly have come from. Just that she specializes in misdirection and sleight of hand.
Electric Wonderland personifies the Rule of Funny in Aerynn Arlia, a Magical Girl with no apparent limits. Aerynn can literally do anything at any time, as long as it's amusing — usually with Buttmonkey NJ as the victim.
Compared to Problem Sleuth and Homestuck, Homestuck's Game Within A GameJailbreak is even more so; Rule of Funny justifies its entire existence. It makes no pretense of having a coherent world or story; Rule of Funny is its be-all and end-all.
Skippys List has the line "I’m funny, so they let me live" to explain why he got away with being a goofball in the US Army.
YouTube Poop takes this Serial Escalation with every second making absolutely no sense in the least, but still being extremely popular with a massive fanbase.
Shiny Objects Videos runs on pure Rule of Funny. Abandon your sense of reality, all ye who enter here.
The Afterlife was never discussed in Season 1 of The Boondocks. However, in Episode 201, Stinkmeaner comes Back from the Dead. This is officially the funniest episode.
The Manatee Gag moments in Family Guy often depict moments that almost certainly never happened (e.g. Stewie and Brian running a talk show). Their prevalence amped greatly following the series' return, which attracted criticism from various other cartoonists and comedians and was parodied in the "Cartoons Wars" episodes of South Park. MacFarlane's response was:
"What should I know about the vast territory that lies beyond the confines of my little subculture of textbooks, Ramen noodles, coin-operated laundry and TV shows that seem to think they can skate by with random jokes about giant chickens that have absolutely nothing to do with the overall narrative? The boys at South Park are absolutely correct: Those cutaways and flashbacks have nothing to do with the story! They're just there to be... funny. And that is a shallow indulgence that South Park is quite above, and for that I salute them." — Seth MacFarlane, in character as Stewie Griffin, Harvard Class Day 2006
Arguably one of the most polarizing points in the show's evolution for fans was when the characterizations became dependant on the trope. Depending on the gag, the entire cast can switch between likeable yet wacky characters akin to the original episodes or Faux Affably Evil psychopaths taking part in high order Comedic Sociopathy. This is even more jarring when originally level headed and more humanized characters such as Lois and Brian join in onthe sadismof a gag.
Spongebob Squarepants takes this trope to physics. For some reason, the characters can light fire, have snow, and running water, while the series takes place under water. Naturally, this leads to Lampshade Hanging:
Patrick: Hey, if we're underwater, how can there be a fi—(fire goes out)
Another one is when a building is on fire. Disregarding the fact that they're underwater, the audience can accept this one. But then SpongeBob grabs a bucket, sweeps it through the "air" and collects a bucket of water to put out the fire. Hmmm...
In "Doing Time" SpongeBob and Mrs. Puff drive over an unfinished bridge with the Mayor at the opening cutting the ribbon, because apparently in Bikini Bottom it's acceptable to open something that's half built.
In the Geronimo Stilton cartoon, Geronimo's cousin Trap is asked to provide a diversion, while the rest of the mains sneak somewhere undetected by pe... other mice. What does Trap do? Pretend on being a space alien (complete with a toy helmet with antennas). Geronimo thinks this is stupid. However, the whole city, even the mayor, fall for it!
In the Avatar The Last Airbender episode "The Serpent's Pass" Toph is rescued from drowning by Suki and (thinking she is Sokka) gives her a big kiss. Even though Toph is blind, there was nothing to stop her from noticing the makeup during the kiss, but the resulting scene is funny.
It's funny because of Toph's deadpan delivery after she figures out it's Suki, not Sokka.
Toph: You can let me drown now.
An instance similar to the SpongeBob example occurs in the Futurama episode "The Deep South", when Zoidberg's house burns to the ground... underwater. Zoidberg wails "How could this have happened?" and Hermes notes, "That's a very good question." Implicitly claiming responsibility, Bender picks his still-lit cigar out of the ruins and puffs on it — eliciting a cry of, "That just raises further questions!"
What makes that really funny is that they explain everything that happens in that episode with pseudo-science (in fact, most of the episode is things being explained away.) But for that one last thing, there's absolutely no scientific reasoning.
Futurama is fond of both this rule and lampshading it. In an early episode, aliens are threatening to invade Earth and the planet sends Zapp Branigan to destroy the mothership. After an epic battle with a massive, well-guarded space installation, Earth succeeds in destroying the thing. Zapp celebrates the victory, before a substantially larger ship pops into view. This, it turns out, is the mothership. When Zapp asks what they just destroyed, Kiff looks at a computer screen, groans and says, "The Hubble telescope." Series producer David X. Cohen said in the episode's commentary track that he knew the joke made absolutely no sense, but loved it so much he had to keep it in.
Lampshaded again by Amy in an episode whose plot gets kicked off by the crew deciding to sign up for the gym. Leela and Amy walk into the Planet Express lounge, where a noticeably-chubby Fry and Bender are watching TV.
Leela: Look at you guys. No offense, Fry, but you've become a fat sack of crap. Fry:Sack? Amy: And Bender; your beer belly's so big your door won't even close. And that doesn't even make sense.
Note to non-fans: Bender (a robot) has a door on the front of his chasis. The door itself is subject to Rule of Funny; sometimes it's a storage compartment for Noodle Implements or for things Bender has stolen, sometimes it gives access to his hardware or software, sometimes it has buttons or diagrams on the inside — whatever the gag of the moment requires. Also, because Bender is a robot, he can't actually gain weight through over-consumption of food or drink, let alone develop a "beer belly".
In perhaps one of the most bizarre applications of the rule ever, the size of the character Endive in Chowder is governed by Rule of Funny. She can vary from about the same size as everyone else, if rather... large, to a towering giant, depending on what's needed for the joke at hand.
Transformers Animated has a scene where Starscream, revived and granted immortality by a fragment of the Allspark, repeatedly tries, and fails, to kill Megatron. You'd probably spend the whole time wondering why the other Decepticons didn't try to get rid of him in any other way, were it not so amusing to see him getting blasted to crap and tossed into a river repeatedly.
In the Justice League Unlimited episode "Kid Stuff" the kidified Justice Leaguers face off against a baby version of the demon Etrigan. There is absolutely no reason at all for why Etrigan should be a baby or why Etrigan should be in this episode at all. One would think that Mordred would have banished Etrigan along with all the other adults, seeing as they've been mortal enemies literally for centuries. But damn if Baby Etrigan isn't the funniest thing you ever did see.
An episode of The Simpsons entitled "Cape Feare" invokes this trope to a significant extent. It was the last hurrah for a number of the show's original writers who were leaving. They threw every wacky or random gag into the episode with the mentality of "What are they going to do? Fire us?" This resulted in one of the most highly regarded episodes of the show ever.
Which makes it even funnier when they do treat it as child abuse. One episode had Homer take fathering lessons. He tells the class a story where Bart, the little dickens, calls him fat. He then casually say 'so then I was strangling him when...' causing the whole group to drop their jaws and question what kind of man he is. Completely played for laughs how they react, and even has Homer reveal that's how he was raised, not that Abe strangled him when he did bad, but that Homer strangled his father every time he tried to punish him. One of the funiest scenes ever.
On the 80's G.I. Joe, Barbecue receives several cryptic phone calls from someone calling himself 'The Viper'. Each call gives information that ends up leading to victories over Cobra, and both sides desperately want to know who he is; Cobra to stop the leak, the Joes who fear an eventual set-up. Finally, the Viper reveals himself he is an older Eastern European man with a thick accent, 'The Wiper' there to 'Vipe Your Vindows'. Now, there are any number of ways both Joe and Cobra could have found this out long before the ba-rump-bump ending, such as hearing the joke before. None of them would have been as funny.
One common mistake in fanfics is to have her doing unusual things because the author thinks they're inherently funny, when the show uses them in such a way that she can only do them when it would be funny otherwise. Think more Looney Tunes less Family Guy.
In the Regular Show episode "Prankless" where a rival park is in a deadly prank war with the protagonists, Muscle Man defeats Gene, the rival park's manager, by scaring him with the illusion of him headed toward the sun. After Gene submits, Muscle Man explains it with mirrors.
There was an episode of the Disney show The Buzz On Maggie in which Maggie got electrocuted by her older brother's hand buzzer, resulting in X-Ray Sparks. It should be noted that this show is a high-school comedy involving insects, and insects do not have inner skeletons.