Ender's Game by Orson Scott Card

You know how little boys can be. They want to fight in the big wars, kill the aliens, and be where the action is. Their tv heroes are always blowing things up and saving the day. Ender's Game gives us a hard sci fi with all the action and adventure one could dream of.

It's the story of Ender, a little boy, who the army decides is the only human who can save the world from the alien bugs. To do this he must lead the world army and commit genocide to the "buggers". He trains in space fighting like it is a sport and then an advanced video game. It almost sounds fun, right? More fun as a book than as a reality, I guess.