This is the OpenChord V1 guitar. It’s a guitar, obviously, but one that works with Guitar Hero and Rock Band.
Right now, the guys behind the guitar only have it up and running with the Nintendo Wii version. That said, Xbox 360 and PS3 versions are in the works.
This video demonstrates what’s going on here:
You can buy the guitar right now for $190. Or, if you’re handy with a toolbox, you can download the source code and create it yourself.
Also, keep in mind that, yeah, playing random notes on the guitar may sound annoying, no one’s forcing you to plug it into an amp. No plugsies, no soundies.