Forget the crapness of the Beamz laser-harp music thing with a real touchless music system: the Theremin. The guys at Popsci have a MAKE-style DIY project online that shows you how to build a pocket-sized version of the classic device. Since it uses a light-level input system, it's a little simpler to build than the RF and capacitance circuitry of the "real" instrument. This means it only costs $18.39 in parts, and about three hours of work if you're neat with a soldering iron. Shaky renditions of "Good vibrations" and the theme tune to "Dr. Who" ahoy! [Popsci]