Kinji Fukasaku (Yakuza Papers, Sympathy for the Underdog) was 70-years old when he filmed his fantastically gory film, Battle Royale - no small feat for a man who should be retired and having trouble getting down stairwells.
A group of ninth graders are drugged, taken to an island, and must kill each other off until one (the winner) is left. It's a social commentary, I swear. Mostly, it's just damn fun.
To use a cliche, it's like a fucked up Lord of the Flies.
I'm not really sure what comparison can do it justice. It just is a film that will certainly stand the test of time.
It's one of my favorites.