In an interview with Rolling Stone Magazine, John Goodman stated that The Dude referring to The Big Lebowski as a "human paraquat" was one of the only improvised lines to make it into the final film. Virtually every other line, including every "man" and "dude," was scripted.
While being a member of the Bowling team, the Dude is never seen bowling.
Before filming a scene, Jeff Bridges would frequently ask the Coen brothers "Did the Dude burn one on the way over?" If they said he had, he would rub his knuckles in his eyes before doing a take to make his eyes appear bloodshot.
A lot of the Dude's clothes in the movie were Jeff Bridges's own clothes, including his Jellies sandals, which he still owns and uses to this day.
Asia Carrera: The girl appearing opposite Bunny Lebowski and the nihilist in the porno that Maude shows The Dude is a porn star.
Charlie Kaufman: In the audience during the interpretive dance scene. Kaufman's own script, Dans la peau de John Malkovich (1999), also contains an interpretive dance sequence.