PERCY JACKSON & THE OLYMPIANS, by Rick Riordan.
THE LIGHTNING THIEF~THE SEA OF MONSTERS~THE TITAN'S CURSE ~THE BATTLE OF THE LABYRINTH
Imagine a cross between Harry Potter and a series of unfortunate events, cram it full of mythology, and you'd have this.
What is it about?
Percy Jackson is a sixth grader suffering from ADHD and dyslexia who discovers that his teachers are not quite...normal. Then he sees the fates knitting socks. In a flashwhirl of events, Percy learns that the Greek gods are currently living on the 600th floor of the Empire State Building, and that his long-lost father is one of the Olympic gods. Because of who his father is, Percy (whose real name is Perseus) is accused of stealing a "divine" artifact of great importance, and to clear his name he undergoes a quest to the underworld. Along the way he meets dozens of characters from Greek mythology.
The books are hillarious! The similies and metaphors are classic. At one point, Percy describing the way monsters smelt said it was "as if a skunk had been living off leftover Mexican food." Great mirth and merriment gained from these books. Furthermore, it helped familiarizing me with the Greek Olympians; my last history quiz required that we know the top 12 gods, and since I'd read these books I didn't even need to study. Take that, academia!