so you've seen the trailers for The Lightning Thief, or maybe you went to see it already, and now you want to read it , but whaddya know, the whole series is checked out. Now what? Here are some other books that you might enjoy that are retellings of, or are based on Greek myths, or just have characters from Greek mythology.
Pandora - you know her, the one who couldn't follow instructions and opened that box; now she has to capture all the evils she let escape.
Secret of the Sirens  This is the first one in the Companions Quartet : "When 11-year old Connie is sent to live with an eccentric aunt by the sea, she discovers that mythical creatures really do exist & an ancient society that has protected them for centuries."
Mary Pope Osborne, the author of the Magic Tree House series, retells the Odyssey  --Odysseus encounters monsters, witches, plagues, in other words, all sorts of troubles, while trying to get home after the Trojan War:
Various heroes and their adventures:
Young Heroes Series  by Jane Yolen:
The Heroes series by Geraldine McCaughrean: