Give this thing a try, it's called Twitch. It's a multi-windowed little game thing part of the Chrome Experiments family, where you can find more things like this.
This is really cool, yes, but I imagine that witnessing this live wouldn't be so great...I mean, you'd just be staring at people sitting on stage staring into screens and such. Also, I'm pretty sure you can program anything to be triggered by anything. It would be one thing if brainwaves were being interpreted into sound, but I'm not sure that's what's going on here.