That's also a real thing now, thanks to the innovative people over at Sony. As part of their Motion Sonic project, they've created a device with sensors and microphones that picks up data from your body as you move and translates your movements into—well, not the next top-40 banger, but some pretty interesting musical sounds. Especially if you're a talented dancer.
The wristband is currently on exhibit at the SXSW festival in Austin. But the cool thing for non-Austinites is that Sony also tapped a bunch of legit dancers and dance troupes to create videos testing out the prototype. And they are really, really cool.