Hot air guitar.
The Voltage Controlled Guitar (VCG) is a breath-controlled synth guitar based on Moog’s Werkstatt synthesizer.
The guitar was constructed on February 15 of this year as part of the Moog/Guthman student design challenge at Georgia Tech’s Center for Music Technology.
You can see the guitar in use in the video below, played by a member of Atlanta-based prog band exStellarator. [via Synthtopia]