Two American companys are currently working on a new generation of game controller. With a strange spider-looking headset which recognizes your brain vibes, you will be able to act in a game only by your thoughts. The technolgy behind works like the electroencephalography which is used for detecting epilepsy and other inter-ictal discharges. But scientists say that controlling a game only by your activity of your brain may be very difficult, because of rather slow reactions in your brain which cause the brain vibes for acting.
source: http://www.heise.de/tr/Spielen-im-Geiste--/artikel/112963, German