Source: http://gizmodo.com/#!5756783/universitys-mega-touchscreen-can-sense-over-100-simultaneous-touches
This is a 33-foot-long curved touchscreen, hacked together by the University of Groningen. Three computers handle the touch detection, one processes it all. It uses six cameras and 16 infrared emitters, plus two or three men to poke around awkwardly in front of it for your amusement. [YouTube via PC World]