I'm currently reading the 'Gone' series by Michael Grant. It has a post-apocalyptic style storyline, where the entire town is survived by kids under the age of 15. Even though it's aimed at older teens, it's pretty brutal to read- lots of violence, cruelty, etc, but pretty good all the same. I'm halfway through but it's taking me a while because I have to stop every now and then to regroup. Cannibalism and an almost-lynching will do that to you!