I went to a talk at Goldsmiths by artists JODI. The piece of work that struck me most was the mobile game they developed called .ZYX. The game makes use of the sensors in the users phone, the accelerometer, the gyroscope etc. as interaction devices. In order to get to the next level, the player must for example spin around clockwise 10 times, or hold the phone still on top of their head for 2 minutes.
Rachel Botsman on TED
I'm not into this sort of stuff (twitter, facebook and raving on the whole web 8.2 or whatever we're on now), but this talk distills down the way it can be used for good (as opposed to facebook type evil).