[youtube http://www.youtube.com/watch?v=sBhOB7CfUoY%5D
Remember those Ebay auctions of air guitars going for several thousands of dollars? We don’t either, but Theremin Hero (more info in the YouTube description) is about as legit as you can get to actually rocking on nothing but air.
Much like using a theremin to control Mario, the vertical antenna acts as the fret board while the horizontal one detects strumming. Combine the output of the theremin with some custom software (yet to be released) and Guitar Hero and you have Theremin Hero Air Guitar.