The Last Apprentice: Attack of the Fiend
All of The Last Apprentice books are fabulous, and they become fabulouser when you read them aloud, and they become most fabulousnest when you read them aloud to your kids (if they are old enough not to be utterly freaked out). Attack of the Fiend brings the devil back to the world of the living... so watch out. Read the rest of 'em too, darn it. They are just extremely well written and the stories told hold together in a way that is unusual for any books, but even more so in books written with younger folks in mind.