I just ordered one. Pretty much lets you midi assign your brainwave patterns to device parameters. This kind of thing has serious potential. This is fairly new technology so it's semi-unreliable, but the fact that it can do it even semi-reliably is really incredible. And it seems like most of the limitations are in the software itself (and the software is still an amazing accomplishment), so considering that and the open source network that's now tied to it, this is bound to make it possible to eventually have complete "telekinetic" control over your music.
If anyone here has played with it, and has any ideas, tips or warnings, I'd really appreciate some input. I want to implement this in the most practical way possible