Rick Riordan's The Lightning Thief
I've been hearing good things about the Percy Jackson series for a while, and don't know why I waited so long to check it out--I mean, you'd think the story of a boy who discovers his father is one of the Greek Gods and has to go to special god-kid summer camp and questing and whatnot would be immediately appealing. And the story was really satisfying--very Harry Potter-esque. It was a little frustrating that some of the major plot points were so easy to guess in advance, but on the whole this book was very enjoyable and I'm definitely going to read the next one in the series. This is perfect bored-on-Christmas-and-needing-some-good-fun reading!