The Lightning Thief Series, by Rick Riordan, is about a boy, Percy (short for Perseus) Jackson, who learns that his real father is Poseidon, the Greek god of the sea.
In book 2, The Sea of Monsters, Percy returns to Camp Half-Blood is in


In book 4, The Battle of the Labyrinth, Percy discovers a maze that could

Book 5, The Last Olympian, is now available where ever books are sold.
My Opinion
In my opinion The Lightning Thief series is a great at book. I liked it not only because it was funny, but because I love Greek

For extra unknown adventures check out The Demigod Files.
Website
Percy Jackson Books