One of Our Thursdays is Missing, by Jasper Fforde

My first purchased book on my Nook, and well worth it. The story is a bit weird; took awhile to figure out just what was going on, and I think I need to read the end again. I'm not actually sure how the story worked out. I think that's more to do with the format and other things going on while I was reading it (on vacation) than the book itself.