Darkhorse Casting: What George Lucas was trying to do, and almost succeeded in doing, when casting for the Original Trilogy. Harrison Ford read the part of Han Solo while they were casting for Leia, and did so well in the role that Lucas finally relented.
Dueling Movies: To a degree the first three movies dueled with the first three Star Trek movies. In the MAD parody The Empire Strikes Out an off panel person hits George Lucas with a snowball. A reader a few issues later suggested that the snowball was thrown by Gene Roddenberry.
Fake Brit: Leia in A New Hope, briefly. Her accent change could be explained as indicative of speaking formally because she is a senator, much the same way Amidala's manner of speaking changed when she was under cover as her own handmaiden, and later when her term as queen ended. Another possible explanation: the scene where her Fake Brit accent is most prominent — when she's arguing with Tarkin on the Death Star. She's talking down to him, letting him know she is his equal and will not be intimidated... but when he points the Wave Motion Gun at her home planet, she drops the pretense and the accent.
Since this is the franchise we're discussing, it becomes a point in the Imperial Agent's storyline in SWTOR that the RP accents used are actually Imperial accents, used in official business when speaking Basic. This makes Leia's accent slip more understandable, as she is dropping her Senatorial mask and reacting like a sane person.
Fan Nickname: Luke's nickname amongst the fans is "Farmboy" or "Wormie". For Palpatine, Sid, Palpy, Palps, or Palpidious. "Vaderkin" to refer to Vader between taking the name Darth Vader and the Mustafar incident. AT-STs are commonly referred to as "chicken walkers."
Flip Flop of God: Over the years George Lucas has made many contradictory claims about the development, conceptual background, and future plans of the series, always claiming that whatever his current plans are is what he had in mind all along. Of special note is the prospect of a Sequel Trilogy. Lucas made statements claiming that he both had and did not have plans to create episodes VII, VIII and IX. For a long time, Lucasfilm's official stance was that the saga culminated with Luke saving his father and confronting The Emperor, and since that had happened there was no need to create further feature films. However, in late 2012 he sold Lucasfilm to Disney Pictures for an estimated $4.05 billion, so they could produce new films every "two to three years" with the franchise continuing "well into the future".
Fountain of Expies: Darth Vader has enough that it warrants its own page. To a lesser extent, Palpatine inspired a lot of "lords of all evil" characters. You can even expect to see a Palpatine-esque character with a raspy voice, dark cloak and rugged looks every time a show wants to display its ultimate villain.
Hey, It's That Voice!: Also overlaps with The Other Darrin - many countries has dubbed the whole original trilogy in the respective languages more than once: The worst offender are the Japanese versions, since only just the first movie was dubbed about six times, and excluding the upcoming Blu-Ray version (and with different voice actors) since the original trilogy was broadcasted by many Japanese networks in the past. This is averted with the prequels, since George Lucas wanted a consistent voice cast between all the movies, regardless the network or media format.
I Am Not Spock: Nearly the entire cast has suffered this to some degree. Most of them have embraced it, while others were left resentful of being typecast (most notably Alec Guinness, the only member of the cast who was a big star before Star Wars). Averted by Harrison Ford, though, who launched a successful acting career outside of the Star Wars films.
Jossed: The ridiculously common theory that "bringing balance to the Force" actually meant equalizing the number of Jedi and Sith (thus Anakin really did bring balance to the Force through Order 66 even if that wasn't his intention) has been firmly squashed by George Lucas who has helpfully clarified that the Sith are the source of imbalance in the Force. "Bringing balance to the Force" refers to destroying or redeeming all of the Sith, thus cleansing the Force of the dark side, which is inherently an imbalance.
In the original release of The Empire Strikes Back, Palpatine was portrayed by Elaine Baker (sort of: Her appearance was superimposed with that of a Chimpanzee's eyes, and her voice, similar to that of Darth Vader's actor, would be dubbed over by Clive Revill). The DVD and Blu-Ray releases of The Empire Strikes Back would replace her with Ian McDiarmid.
Likewise, Boba Fett's voice was changed from Jason Wingreen's voice to Temuera Morrison's voice in the Original Trilogy's first DVD release to reflect Boba's status as a clone of his father, Jango Fett.
Playing Against Type: An interesting retroactive case for Mark Hamill, who's spent almost his entire career since these films playing villains, the nastier the better. Luke Skywalker now kind of comes off as a piece of Early Installment Weirdness for him.
Promoted Fanboy: Nearly three generations have grown up with Star Wars, so almost anyone working on modern projects is one of these.
Real-Life Relative: Wedge Antilles's actor (Denis Lawson) is the uncle of Ewan McGregor, who plays Obi-Wan. Famously he tried to talk his nephew out of the role, fearing that, like his own career, McGregor would meet with early success and then a nosedive. He was wrong and this was actually McGregor's breakout role, and Lawson has had a mild resurgence himself on British TV.
The battle was finally featured in the single-player campaign of Star Wars Battlefront 2, where the rebels received an epic curb-stomping by some verypissed off 501st veterans. How the ceremony at the end of A New Hope fits into this was initially unclear, but The Essential Guide to Warfare establishes it took place not long after the Death Star battle, while the Battlefront 2 fight happened during a subsequent several-month-long siege of the Yavin System by the Imperial military.
Lucas originally wanted to make a movie of Flash Gordon, but wasn't able to secure the rights from producer Dino De Laurentiis - who would later make the Flash Gordon movie after Star Wars took off.
Lucas then turned to the films of Akira Kurosawa for inspiration, and wrote a script that was pretty much a remake of The Hidden Fortess - IN SPACE! He considered buying the rights to that, but decided to develop his own story further.
Many things were considered over the years, considering the vastness of the franchise. A major thing to consider is that George Lucas originally wanted to serve as a mere supervisor as nine films were made under different directors, and looking forward to seeing how the franchise evolved with different people Running the Asylum. As things continued on (Possibly due to a disasterous incident of "leaving it in someone elses hand") he took more direct control of The Verse. The more recent Star Wars television productions seem to be him trying to salvage what was left of that original intent.
In the Leigh Brackett first draft script of Empire, Vader and Anakin were two separate people; Anakin showed up to Luke as a kindly Force Ghost. Also, Luke's twin sister was not Leia but someone else, a girl called Nellith who was mentioned but never seen, in an obvious Sequel Hook.
The basic story of the original trilogy was intended as a single movie, beginning with the hero's journey to become a Jedi and ending with the defeat of the Empire with the destruction of the Death Star. Realizing how immense that project would be, Lucas opted to not tell the defeat of the Empire in a single movie but keep the destruction of the Death Star (which is why the Death Star II came into play as well as another forest planet being involved). Lucas also coalesced the backstory notes into what became the foundation for the prequel trilogy, deciding that an entire trilogy happened before the original films. In each trilogy, the story grew far beyond the original intention.
Much of this is covered in Michael Kaminski's The Secret History of Star Wars, which painstakingly goes over documentation from the very earliest days of the project to show how Lucas developed and transformed his original vision, especially the idea that Luke's father and Darth Vader were two different people.
According to George Lucas, the whole series was supposed to have a Framing Story with R2-D2, the last surviving member of the main cast, telling an advanced future race about the fall of the Republic and the rise and defeat of the Empire.
A New Hope was originally going to be released around Christmas 1976 (much like how Episode VII is going to be released in December of 2015), but was pushed to May of 1977.
Palpatine was originally conceived as an Anti-Climax Boss, a power-hungry dullard manipulated into the Galaxy's top spot by Vader and Tarkin, who ran things behind his back. Notably, this detail was changed so late in the universe concept that it made it into the novelization of A New Hope.
Lucas long argued that the prequel's story existed in some form or another from the beginning of the saga, as the films featured the subtitles, Episode IV-VI (although the subtitle "Episode IV" wasn't in the first Star Wars film until its 1981 video re-release). A New Hope and a few elements of the original trilogy also make slightly more sense when seen against the backstory in the prequels, though others are more complicated.
Another notable example is Chewbacca's not getting a medal at the end of A New Hope. The official explanation is that such things are against the Wookiee religion — except that the original official explanation, from the Official Star Wars Fan Club, was that he did get one but Leia wasn't tall enough to put it around his neck.
Writing by the Seat of Your Pants: Sort of. Lucas did have an over all Myth Arc plotted out, but as the production of the films went on the story grew more and more. The version we know is hardly anything like the original story Lucas planned.
There are two major fan organizations of cosplayers - the 501st Legion, aka "Vader's Fist", is composed of people who make and wear the various "villain" costumes. They take letter-number designations, the letters reflecting their costumes - someone who wore a stormtrooper costume would take the prefix "TK", for example. In reaction to the 501st, the Rebel Legion was formed. There is significant overlap between the two, and they're the next thing to professional in keeping standards.
The infamous "Hello Kitty Vader" is actually a photoshop of a 501st member's white Vader.
In Outbound Flight, there is a female Chiss admiral in white whose name is Ar'alani. A few years before the book was written, Zahn met and eventually became friends with a fangirl named Ari Roselani. When they met, Roselani was cosplaying as Mitth'raw'nuruodo (better known as Thrawn), a male Chiss admiral in white.
Noriyoshi Ohrai's poster designs for the promotion of the movies in Japan are so popular that other countries have adopted the same design.
Animator Nelson Shin (Who would later become the executive producer of the original Transformers cartoon and found AKOM) was the creator of the famous Lightsaber effect for the first film. Later films have it done in-house at ILM.