I looked into the Neurosky and Emotiv headsets the other day for a side project. They've been on the market for a while, but most reviews are pretty cautious.

The Neurosky headset appears to suffer from inconsistent readings, and is mostly really good at picking up muscle movement (head turning, blinking) - great if that's what you're after, but terrible if not.

http://www.colorfulwolf.com/blog/2009/12/13/mind-control-for...

The Emotiv headset has some mechanical issues - the pads are a pain to wet and place and keep falling out. The data also appears to be super encrypted and quite hacker-unfriendly, so I stopped reading there.

http://www.joystiq.com/2010/01/27/review-emotiv-epoc-tough-t...

http://thingist.com/t/item/23089/ (some angry words)

Interaxon demoed a mind controlled version of a Zen Bound 2, a game I've worked on, few years ago. http://vimeo.com/18307473

I never got to test it though.

With the wide spreading of gamification, also mind-controlling videogames are here.