When you're driving in the same direction for a while, and you realize you've forgotten something and have to go all the way back, you must "throw a u-ball". U-ball is just another word for u-turn but with u-balls you cover a much greater distance.
J: Paul, did you remember the money?
Paul: Aw shit. I forgot. Now I have to throw a huge u-ball. Fuck!
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).