The Lightning Thief by Rick Riordan

Poor Percy. He's been kicked out of six schools in six years for being a troublemaker but he doesn't begin to know the meaning of trouble until his math teacher turns into a monster and tries to kill him while on a class visit to the museum. It turns out that Percy's dad is a Greek god, Poseidon, no less, and life for the offspring of the immortals tends to be dangerous and short. Percy must head to Camp Half-Blood where along with other children of Greek gods he can learn skills that will help him to survive. But after being accused of stealing Zeus's lightning bolt he must set out on a quest to find it before all-out war breaks out between the gods with humanity as the casualty.

There is plenty of action in The Lightning Thief but it is also laced with lots of humour, much of it emanating from the modern twist Riordan gives the Greek gods. The Camp Director happens to be Dionysius, punished for some past infraction by being forced into doing good works with youth; Mount Olympus is on the 60oth floor of the Empire State Building; chapters have amusing titles such as "Three Old Ladies Knit the Socks of Death".

Kids who are not familiar with Greek mythology may be tempted to do more background reading. Those who are, will be amused by how Riordan incorporates the ancients into a modern story.

Highly recommended for tweens.