Its title notwithstanding, The McSweeney's Joke Book of Book Jokes isn't really a joke book. It's a collection of miscellaneous pieces from McSweeney's Internet Tendency which all have something (loosely defined) to do with books, or fictional characters, or authors. Most of them are funny. Some are not. John Hodgman penned the introduction, which was funny. Darby Larson penned "Don't Read This or You Might Get Poked in the Eye With a Dagger," which was not.
Among my favorites: John Moe's "Winnie-the-Pooh is My Coworker," Ann Asher's "A Lost Scene Involving Louis, a Turkey Character Cut During the Final Edit of Charlotte's Web," Laurence Hughes's "Lady Macbeth on Ambien," and Ben Joseph's "Celebrity Biographies Written by a Guy Who Cannot Distinguish Fiction From Reality."
If you're a fan of McSweeney's-humor, and didn't catch these as they came through the site originally (or if you just want to have them all in one place), this is a book for you.