A
staple line of
Dude, Where's my car? I have yet to see it in any other movie, tho.
Synonyms include Dude! Sweet! Cool!
The first person in the movie to say it was Gene, the guy in the closet, played by Stuttering John.
Usage:
Chester: Dude, you totally touched Christy Boner's Hoo-hoo.
Jesse: Shibby! Low five!
czeano notes that it's implicating marijuana use which is mentioned in the audio commentary on the DVD.
The phrase itself was trendy for a time, but isn't heard much now that people seem to have forgotten the movie. This was similiar to the Jim Carrey movie The Mask, where people would say "Ssssmoking!" when the film was in vogue.