Percy Jackson and the Olympians

Many of the characters are ancient, but the cool factor is brand new. Troubled Percy discovers he's a demigod (surprise: his absent dad is Poseidon!) and that evil forces want him dead. He finds asylum at Camp Half-Blood where he learns to use his powers and finds allies in the quests that await. It's a potent mix of magic, danger and whip-smart dialogue that kids will devour.