Percy Jackson is not a normal 12-year-old. Strange things always seem to happen around him, and he has a problem with getting into situations that lead to getting kicked out of school. Things get even stranger when, on a class field trip, Percy vaporizes his (really creepy) math teacher (a monster in disguise) and learns that he himself is a demigod. A whole new world is opened to Percy when he goes for the summer to Camp Half-Blood, where he meets other demigod friends and finds out his father's identity. Of course, he immediately gets plunged into a quest to save the world.
The Lightning Thief, the first book in the "Percy Jackson & The Olympians" is a wild ride and makes you run to the library to pick up book #2, The Sea of Monsters (there are five books in the series currently). The library has the audiobook in downloadable and CD form - it's worth a listen because there are some great voices on it. The official book Web site is very cool with descriptions of all the good guys and bad guys, videos of Rick Riordan talking about the story, and some games. A movie is currently in the works as well. If you love Greek mythology and hair-raising adventure (plus some really funny dialogue), check out The Lightning Thief.