There's a Japanese film called Battle Royale about a class of teenagers dumped on an island and given a bag containing random weapons. One kid gets a frying pan. They have three days to kill each other until only one is left, and if more than one is left the collars around their necks explode, killing everyone. Think Hunger Games, but with an 18 certificate and made in Japan.
trailer - http://www.youtube.com/watch?v=N0p1t-dC7K