As soon as I raise funds to buy a kit from PAIA electronics, I'll build one and post sound clips of me playing it (hopefully well). The instrument is really intriguing since it is played without touching it. It operates on the heterodyne principle where a frequency can be generated from the difference of two other frequencies. In the case of the theremin, the audio frequency is the difference between two carefully tuned oscillators with one which is affected by the distance between the performer and one of the antennas.