[quote name='neocisco']I've walked out of Chronicles of Riddick and Kung-Fu Hustle. [/QUOTE]
I've never walked out on anything myself (I tend to only go to the theaters when there's something I must see or my friends are dead set on a good movie with solid reviews), but almost everyone I've talked to has said that Chronicles of Riddick was one of the worst movies they've ever sat through/walked out on.
My roommate's anecdote was better, though. He decided to sit through the entire thing, regardless. The second the movie ended he turned to another friend and said "You owe me for this!" and his friend's response was a bowing his head in shame and replying, "Yeah, I thought as much..."