When someone starts going on about the life-changing role the Star Wars movies have played in their developmental years, casually announce that you've never seen any of them, but hear they are "pretty good."
Get important terminology wrong -- this drives the true fanatic nuts! Confuse Wookies with "Winkies"; call Yoda "Yodel"; refer to Return of the Jedi as Revenge of the Jedi, Phantom Menace as Planet Menace, and Attack of the Clones as Send in the Clowns. Get very annoyed when corrected.
Get the names of the key characters wrong, or better still -- forget them. "You remember the guy from these movies, you know, the one with the plastic head and the respiratory problem?" or "Oh, yeah, Ben-Wa Kenubi, my favorite, played by that English bloke. Wassisname. Sounds like a beer or something." Insist that The Empire Strikes Back is the only worthwhile Star Wars movie because it is "sooo dark."
Deliberately confuse science-fiction universes and inhabitants. Double fun and satisfaction as this offends two sets of rabid Nerdocracies at the same time. For example, insist that Luke Gripewater is fighting for "The Federation" and that Chewbaccy is a Vulcan. Insist that "to boldly go where no man has gone before" is a Jedi commandment. Brush off any attempt at correction with a dismissive "whatever. As if anybody really cares."
Make vaguely unsettling insinuations about George Lucas. Try "isn't he involved in some sort of DNA-cloning controversy?" or "I hear he only talks to his mother via a TV monitor," or "I read this piece where he said Star Wars was written for people who hate sex." Insist that there is a "latent homo-erotic subtext" to the Han Solo/Luke Skystalker relationship and you are uncomfortable with Lucas' "non-critical, neo-Nazi aesthetic." When asked what you are talking about, roll your eyes and refer to the "blatant homage to Riefenstahl's Triumph of the Will" at the end of the first movie, then add, "Don't tell me you didn't notice?"
When some sad sack describes the insane lengths he went to for Attack of the Clondes -- camping out on the street, taking time off work, neglecting loved ones, not bathing and so on, respond by saying someone "in the business" gave you a couple of free tickets to the official opening, but you lost them and add, "Funny, that's the first time I thought about it." When they just won't shut up about how it's the most spectacular movie event of all time and how you would have to be a moron not to dedicate every waking moment to it, simply say, "Yeah, my little sister and her little friends get a kick out of it all. You know how it is with these pop space movies."
The ultimate is to play stupid that the movie was even a big event. "Attack of the Clones? Yeah, I heard something about that in the local newspaper. Something about the guy that made the first four is going at it again or something? Dunno ... "
When someone is sitting there theorizing about how there's probably secret messages and things you can see if you look closely in the movie, just calmly sit there and say in a whisper, "Then I guess you haven't played it backwards in a VCR before?" Try not to laugh as the person (attempting to look calm and collected) slowly gets up, starts walking out of sight, then see him bolt down the street towards their house to try it. Depending on how avid of a fan the person is, look for the smoke trail.
To make the last suggestion even more fun, wait for them to call back after they have gone through the whole movie backwards and couldn't find anything in Phantom Menace. Tell them, "Oh, that's right, it was in one of the other three episodes." When they tell you the lengths they went through and the sleepless nights spent trying to get a pirated copy before everyone got to see it in the theater, tell them, "That's funny, I simply called the 1-800 number that was all over the Internet and got it mailed to me the same day, three weeks before the movie came out."