I just finished reading Letter to a Christian Nation, by Sam Harris, and wow. Definitely one of the best non-fiction books I've read in a long time. It's fairly short--114 pages-- and I definitely recommend it if you've got a couple hours to spare. Atheists/agnostics will get a kick out of it, and religious folk...well, you'll probably be foaming at the mouth by the end, but it's still worth checking out.