Yesterday I got What If?: Serious Scientific Answers to Absurd Hypothetical Questions by Randall Munroe. I started reading it today on the bus and let me say, it's a gem. I've been looking at his website, http://xkcd.com/ for a while now, and I love it. Some of his comics go over my head, I don't always understand the math, the science, or the computer jokes he makes, but I still love it.
He's even got a what if? website where he posts some of these. I highly recommend that you check out one or all of these. They're pretty funny. His book is available at Amazon, as well as a few other places. I even saw it at a local bookstore last week!
What have you been reading lately?