Did you know that the scene in Star Wars Episode II where Obi Wan eludes Jango Fett's ship in the midst of a dense asteroid field is scientifically impossible?
If you're in the mood to scientifically nitpick Star Wars Episode II or a number of other SF films and TV shows, check out Bad Astronomy. This site is fun (the author loves his subject, but doesn't take himself too seriously) and informative. Check it out.
(That scene is impossible because in a planetary ring system the "asteroids" would have long-since ground each other to dust particles.)