At the show last night I played the Guitar Hero X-Plorer controller. No, really, as if it were a real instrument. Like, I could actually determine whether I played a C or a D.
After the show people asked me how I did it. XNA easily interfaces with the X-Plorer controller as a standard xbox 360 controller. So I built a little C# program (after learning C# with some of Jude’s help) using XNA and the C# MIDI Toolkit to map the controls to MIDI notes (in a clever way, see the program documentation for more details) and output to a MIDI Yoke port which was read by Reason. Then I just used Reason’s excellent guitar and synth patches and played away. There will be YouTube videos of the show soon :-).
The C# program is here, called Guitar Hero Hero, and here is the source.

It was Awwwww-Summmmm!!!!!
A Danish “Commodore 64 band” did something like that for a few years ago, there’s a video recording here
http://www.pressplayontape.com/?pid=cannonfodder
I like your music :-)