Kinect has become rapidly popular. Here is another hack of this 3d camera. Earlier this year, the pong-wall was featured in Tetalab. This pong-wall uses the MAX7313 16-Port I/O Expander with LED Intensity Control, Interrupt, and Hot-Insertion Protection chip, to control the LEDs. A Ping-Pong ball cut in half and placed over each LED performs a diffuser.
Recently, they got the wall a step further. The kinect is connected on a PC, which processes the image data and converts it into gradients. The data are then transferred to the LEDs on the Pong Wall. The image processing is done with the Open source Kinect drivers.