Here's a cool project submitted by reader Lello La Barbera. What you see here is a theremin based on Theremino, a modular system for connecting multiple sensing and output devices together with real time communication. Theremino actually stands for "The Real Modular In Out".
This theremin uses the Theremino's CapSensorHQ module for capacitive sensing. The body was created with a 3D printer. Click the picture above for a higher resolution version of the photo.