Dusk

Hotel Dusk is a new game for use with the Nintendo DS that might catch the interest of those interested in taking books to the electronic sphere. In order to play, the system has to be held sideways, like a book, then one must read and interact with the characters using the stylus in order to proceed. To get an idea, open the book and go to the Easy Touch Navigation paperclip.

The title is reviewed at Wired. And also described at Wikipedia, of special interest is the Gameplay section.

It is not quite at the stage where holders of Chapters stock should be worried, but I can see how a casebook could be utilized in such a format.