How many of you have heard of the commercially produced versions of this idea?
Firstly there's the rather erratic OCZ NIA (Neural Impulse Actuator) http://www.ocztechnology.com/products/ocz_peripherals/nia-neural_impulse_actuator
Known for being rather unreliable, but improving reaction times in games...
And the far more impressive looking Emotiv Epoc.
http://www.emotiv.com/
Both of which demonstrate relatively cheap commercially produced EEG machines designed specifically with gaming in mind.
Still, as a technology for this, EEG still leaves a lot to be desired. You have to 'train' the computer to recognise your thoughts, and it apparently requires an insane amount of concentration to use one of these devices to actually control anything.
Personally, I'm interested, but only if it can improve the amount of control we have over games.
I find most gaming environments incredibly restrictive with regard to what you can do in them...
(Consider that the human body amounts to having 60+ degrees of freedom even in a highly simplified model; No game controller setup I can think of currently gets much past 15 degrees of freedom worth of controls.)