Star Trek vs. Star Wars
There's another one that is mostly combat footage, hence less choppy (and much shorter).
And finally, this Robot Chicken clip shows what happens when you get fans involved.
Ok... when I said finally I lied. I watched something, and to share the suff- I mean joy, I'm going to see if embedding objects works in blogspot. If it doesn't work, you are missing some Australians doing a "live" version of the Star Wars Gangsta Rap, which means they lip synch and show how white they are.
Be glad... I just found another live version that looks like 2 guys in a dark room with a web cam. I'll spare you.