Trivia: At the beginning of the movie, when The Dude is writing a check for the cream at the grocery, look at the date on the check. Sept 11, 1991. A few seconds later we see George Bush Sr. talking about Iraq. So here we have a scene containing Sept. 11th, George Bush and references to the Middle East in a movie that takes place in 1991. (00:03:00)
Trivia: This isn't really a mistake, just something to note - throughout the whole movie the Dude is not seen bowling once. Also, every time you see Donnie (Steve Buscemi) bowl, he gets a strike, except for the last bowling scene, he does not get a strike, and he dies of a heart attack a few minutes after this.
Trivia: In the original script, the Dude's source of income (in order to explain his nice apartment despite being unemployed) was going to be briefly explained - he was related to the inventor of the Rubick's Cube, and was living off an inheritance. It was eventually deemed unnecessary, and thus removed.
Trivia: The Dude is kicked out of the cabbie's car because he hates the band "The Eagles." The Dude's bowling rival Jesus was introduced much earlier in the film with a Spanish-language version of The Eagles song "Hotel California" playing in the background. One of those many nice details you don't necessarily notice the first time you watch that subtly ties the movie together.
Trivia: Woo and the other guy who work for Jackie Treehorn trade outfits when they come back to tell the Dude that Jackie Treehorn wants to see the deadbeat Lebowski. (00:03:50 - 01:13:50)