Here’s a pretty cool mod for the Guitar Hero World Tour drum set that allows you to trigger the kick drum by blowing into a tube. Modder extraordinaire Ben Heckendorn received "a request to build an alternative to the GH4 drum kit’s kick pedal for a person who uses a wheelchair" and managed to whip something up with a little bit of PVC pipe, some hot glue, and a rubber glove.
The GHWT kick pedal apparently contains "a piezoelectric sensor which creates a small voltage when impacted" and the idea behind the mod is to make it so the sensor reacts to air pressure instead of the pressure that’s created when your foot presses the pedal down.
If you’re handy and have all of the necessary parts lying around, it doesn’t look like this project would take too long — maybe half a day or so. Check out the full instructions here along with some notes on how this mod would work for the Rock Band drum kit.