Brain-pong!
I gotta say: wow! I had a great experience this week, because I’m a subject in a research for which I have to play a computer game with my thoughts!
It’s called BCI, for Brain-Computer Interface, and you have to wear a really silly-looking cap stuffed with electrodes. Using the signals from the electrodes, your thoughts are read. Not the words, thank god, but your intention to move. The theory is like this: when you are commanded to move say your finger and you move your finger, a certain area of your brain activates. When you decide on your own to move a finger, this same area in your brain activates, along with another area concerning your decision to move that finger. This can be read through EEG and can therefore be used to control, in this case, a computer game!
In this specific research, you imagine moving your hand to control a little on-screen ball, and it works quite well. I’ll tell you, it’s pretty cool to see a response to your imagination 
One downside for me though: today the signal contained a lot of static and they spent a long time debugging but couldn’t get it good enough to use. It turns out that, because I have such short hair (which seemed so handy at first) the skin on my head is tougher than average, resulting in a poorer signal… They’ll try to give my head a good scrubbing next session and hope that’ll work to get a better EEG, but if not then it’s no use continuing these experiments on me. God, I hope it’ll work! Oh well, at least if it doesn’t, I won’t have to look like this anymore (note how awake I look, could that have anything to do with the signal being poor?):
