What's the last book you read where, if asked whether you thought reading it had been a good way to spend your time, you would not just say "Sure, I think so," but "Hell yeah!"?
I went through my last couple years of reading and seem to have a rate of about 1 in 10 hell yeahs. Most recent hell yeah is Tehanu, in the Earthsea cycle by Ursula K. Le Guin, and in nonfiction, Freedom Ship by Marcus Rediker.
@scott tehanu is great. Recently hell yeah reading... Tusks of extinction (short story) Children of time (novel), there is no antimemetics division (novel)