We can't all be Jean Michel Jarre, but thanks to the Arduino microprocessor we can flail our arms around and make music. Omer Yosher's "Airpiano" is a long strip of motion sensors treated as, via the Arduino, midi keys and faders; moving your hands over and through the sensors control notes or samples, as well as volume.
Video demo after the cut
LEDs embedded in the long controller strip give visual feedback as to your movements, and the full length of the Airpiano is equivalent to an octave's worth of notes. Of course, since you're firing off midi messages it's just as easy to trigger samples, clips, or multiple other things.
Connectivity is via USB, which makes it portable, and accompanying software is used to assign presets and transpose notes. The Airpiano went on show as part of the Berlin Design Festival; unfortunately there are no plans, as far as we're aware, for a commercial release.