name your favorite twisty movie (movie with twist at the end, no spoilers)

[RockRaven]

36. I saw The Sixth Sense the night it opened, was surprised how many people brought their little kids

I'm no prude, but the movie was rated R (IIRC) and based on the trailers was obviously a suspense/horror film, and I was at the last showing of the night -- maybe 10PM or so -- and I was in a very over-protective/yuppie/helicopter-parenty kind of town. About 1/3 of the adult couples/groups in line had a kid the age of the main character or younger. I could understand if they'd seen it already and decided it was okay for their kids, but it was opening night so that's unlikely. Whatever.

Anyway, I've seen/heard a lot of people say this ending was trite/obvious, but I thought it was very effective not so much on the grounds of surprise but because of how significantly it changes the dynamic between all the major characters in the majority of the preceding scenes.