Already on my wishlist! Added to the fact that it comes in a kit (got to go fetch the old soldering iron and brush up my fairly limited soldering skills!), it is a very interesting piece of hardware to extend the Pi’s functionality and play even more with it.
There are already a number of Python libraries meant to control the Pi’s GPIO pins, enabling it to interact with the outside world (eg, it could be interesting in a home automation project!…).
Sometimes I’d like to have more time for this kind of activities, sadly it is something that can only be done while on vacations, which are getting shorter every year!… 🙁