I'm actually reading the Heroes of Olympus books again too. It's one of the few book series that I actually own. They're fun. Plus, I need to reread this series so I can properly reread the Trials of Apollo books (I've owned the fourth one for months, but haven't read it yet). Although I find it ironic that the author doesn't like the thought of people writing fanfiction about his books. A lot of his books are literally fanfiction of Greek/Roman/Norse/Egyptian mythology.
Speaking of Greek mythology, I recently read The Odyssey. It's a really neat book and I like it a lot despite never really being into Greek mythology books but it's nice.