I have to admit, I'm a little prejudiced against it because it sounds like a Harry Potter knock-off. Plus, I've already seen the movie (which wasn't very memorable).
But in the first few pages I came across this passage. Percy Jackson is the narrator:
Grover and I sat on the edge of the fountain, away from the others. We thought that maybe if we did that, everybody wouldn't know we were from that school -- the school for loser freaks who couldn't make it elsewhere.
"Detention?" Grover asked.
"Nah," I said. "Not from Brunner [the history teacher]. I just wish he'd lay off me sometimes. I mean -- I'm not a genius."
Grover didn't say anything for a while. Then, when I thought he was going to give me some deep philosophical comment to make me feel better, he said, "Can I have your apple?"
I was totally not expecting that. In fact, I was waiting for the deep philosophical comment too.
It's nice to be surprised like that.
Read my review here.