Why not watch 167 theremin players perform variations on Beethoven's Symphony No. 9? Yeah, okay:
All right, let's unpack this a bit. The players here are using devices called Matryomins. They're single-oscillator theremins that happen to be contained inside a matryoshka doll, also known as a Russian nesting doll. Here's how a single player interacts with this kind of instrument:
Neat, eh? Apparently you can buy a Matryomin online if the language barrier isn't too great. Now you just need 166 friends to come over.