Now, that's a bright idea, writing a collaborative book altogether. When Phil McArthur came up with the idea of writing a book, he figured out that it might be a good way of collecting money for charities. This is why he auctioned his book on ebay.
Actually, he auctions empty pages of the book, to be filled out by other people. The 251 pages novel, a thriller, has gathered 22 pages, all from authors from different countries and can be found at NovelTwists.com. All profits of his venture go to Macmillan Cancer Support and Phil has managed to collect over $150 until now.
If you want to support this noble project, click your way to Novel-twists page on ebay. At time of writing there was in the region of 220 pages left, all with a starting bid of $0.01.