The Humble Ebook Bundle -- a two-week, pay-what-you-like, DRM-free ebook sale -- has just revealed the four bonus books in week two: XKCD Volume 0 by Randall Munrow; Signal to Noise by Neil Gaiman and Dave McKean; Poison Eaters and Other Stories by Holly Black and the bestselling Machine of Death anthology. To get these bonus titles, you have to pay more than the present average for the books (if you bought already and paid more than the average at the time, these books are already yours to download, otherwise, you can top up your payment to get them). Remember, you can also buy the bundle as a gift-code to give to a friend!

(Reminder: the Bundle also includes Peter Beagle's The Last Unicorn; Wil Wheaton's Just a Geek; Lois McMaster Bujold's Shards of Honor; Robert Charles Wilson's Spin, Cherie Priest's Boneshaker and my Little Brother)