Some trivia from Star Wars Episode III: Revenge of the Sith
* This is the only Star Wars film to receive a PG-13 rating from the MPAA; all previously released films in the series were rated PG. Interestingly, A New Hope was originally rated G, but its rating was deliberately pushed up in order to attract a broader audience.
* Famous characters from the original trilogy that make their first chronological appearance in this movie include Chewbacca, Luke Skywalker, Leia Organa, Grand Moff Tarkin and Darth Vader. Scenes with Mon Mothma and Lorth Needa were deleted.
* In the scene where Darth Vader and the Emperor are looking out onto what looks like the unfinished first Death Star, Grand Moff Tarkin can be seen.
* Anthony Daniels (C-3PO) and Kenny Baker (R2-D2) are the only actors to appear in all six Star Wars films.
* Playwright Tom Stoppard reportedly did an uncredited re-write or dialogue polish on the script. Hayden Christensen confirmed this in an interview for Playboy magazine.
* Bai Ling filmed minor scenes for the film playing the role of a senator, but her role was cut during editing. She claimed that this was because she posed for the June 2005 issue of Playboy magazine, whose appearance on newstands coincided with the movie’s May release, but George Lucas denied this, stating that the cut had been made more than a year earlier, and that he had cut out his own daughter’s scenes as well.
* Grauman’s Chinese Theatre a traditional venue for the Star Wars films is not showing it this year. However, a line of people have stood there for more than a month hoping to convince someone to change this. So far, this Star Wars Line has been unsuccessful.
* This is the only time you see two lightsabers of the same color (blue) battle (Anakin and Obi-Wan’s). One could also consider the lightsaber duel between Obi-Wan and Grievous, the latter wielding green and blue lightsabers.
* In Episode VI, Princess Leia tells Luke that she remembers her “real” mother being sad when she was very young. In Episode III, Padmé dies almost immediately after childbirth, so either Leia is misremembering her “real” mother or as a force-sensitive, she remembers Padmé from the few seconds both were alive at the same time.
* Darth Vader/Anakin Skywalker, Obi-Wan Kenobi, C-3PO and R2-D2 are the only characters to appear in all six Star Wars films.
* Hayden Christensen had to look through the mouth-piece of the Darth Vader costume, not the eyes.
* When the ship Anakin and Obi-Wan are on at the start begins firing on an enemy ship, there is some footage of explosions and guys being thrown into the air. One of them screams a classic “Wilhelm scream”.
* Gary Oldman was originally supposed to provide the voice of General Grievous, but he backed out after learning the film was to be made outside of the Screen Actor’s Guild, of which he is a member.
* George Lucas confirmed in an interview that Steven Spielberg tinkered with several action sequences in ROTS. This happened when a project of his fell through and he had some spare time. Lucas sent over an animatics artist to assist him. It is rumored that the scenes he worked on included the Yoda/Sidious battle and a part of the Mustafar duel.
* Count Dooku saved Anakin’s life by cutting off his hand in Episode II. If both of Anakin’s hands had been organic instead of a mechanic prosthesis, they would have burned away when Anakin fell into the lava on Mustafar, and he would never have been able to drag himself to a safe enough place to survive for the few minutes he had to wait until he was rescued by Palpatine’s troops.
[Info from wikipedia.org (It's a summary in there, don't read if you want to watch this movie!]