Well, this sure seems like the future: a holographic display that responds to touch and can be physically felt. Even cooler? It's made using two hacked Wiimotes!
The video does a great job explaining it, but here it is in a nutshell: the Wiimotes sense where your hand is, telling the holographic image to adjust based on your location. Then an airborne ultrasound tactile display creates the sensation of touch. I don't know what the practical applications of this are, but it's totally awesome.