I found this fun project over on the Make blog.
"Use your Wii Remote as a MIDI controller! Controlling your favorite music software with a Wii Remote is actually much easier than you might imagine. You don't have to hack your Wii Remote or buy expensive software. In fact, the software is free and you most likely already have the hardware. This tutorial covers basic instructions for use with a PC. It is possible to do this with a Mac but it will require different software."
Full details of the tutorial can be found at http://weareaudiobody.com/164101129
If you liked this you might also be interested in their Tennis Ball & Lego Ableton Controller