I just finished reading one of the single funniest books I've ever read. It's called Apathy and Other Small Victories and it's written by Paul Neilan. I've never laughed out loud so often. It's dark and totally unsparing of anyone or anything. And it's hilarious.
Here's the best one-sentence description of the book I've seen:
If Camus and Bukowski had written A Confederacy of Dunces and combined it with the screenplay for Office Space, it would have been this book. A triumphantly, weirdly hilarious comedy.
--Neil Pollack, author of Never Mind the Pollacks
Here's the Amazon link if you're interested.