Now, there are officially three things you can do with a theremin: you can score a low-budget sci-fi film; you can join a prog rock cover band; and, as of today, you can play Super Mario Bros, awkwardly.
YouTube user conquerearth hooked up his theremin to a PC, mapping its tone—which, for those of you who haven't been to a science museum in a while, is modulated by your hand's proximity to the device antennae—to a rough approximation of joystick input, which is then translated to the basic left/right/jump/run controls required for Super Mario. It works fairly well judging by the demonstration, and considering theremins were invented nearly a century ago, I'm guessing without gaming in mind. That said, I do think the video could have done with a slightly different score. [Nowhereelse]