Following that excellent book review for The Last Olympian praising Percy's sense of humor, I had to pick just a few lines from the book to illustrate. Riordan's writing is just too good not to share.
"A blade was supposed to reap my soul. As a general rule, I preferred not to have my soul reaped." p. 56
"He seriously needed to keep a pack of Aloe Vera Kleenex in his armor pocket, because that nose was wet and red and pretty gross." p. 186
"If you're heading downtown from Central Park, my advice is to take the subway. Flying pigs are faster, but way more dangerous." p. 250
The books are chock full of that kind of fun. Nothing like a dry sense of humor to make you snort in public. (Not that I would ever snort anywhere - I'm much to classy.)