I like Little Fears a lot, although my group doesn't play it very often as some of us have small children and this game can be unsettling. The game contains certain elements such as missing children, physical abuse, and child molestation. Of course all these are optional just in case any of your players might be sensitive to the depiction of such things. The system itself is quick and fun, and has the feel of a child's game. You basically rate yourself for a few stats, make a note of what you are good at and what you suck at, and scribble down a ine detailing what you have in your pockets.
Depending on the tome of the game, the mortality rate can be high. In our first game, all of the children but one were lost in the shadowy land inside the closets. The one survivor has, unknown to her, been invaded by a succubus that will remain dormant inside of her until she hits puberty. What will happen when the demon finally awakes and takes over the host child? Well, that's another game.
Not too long ago I was discussing on Forge.net the possibility of adapting the concepts of Little Fears to the world of angry and troubled teens. We have yet to put this idea to the test.