I made this small game for christmas to the child members of my family, but it turned out that the older generation also loves it. I've used a kinect camera and an open source (OpenNi) framework to idetify and separate players. Each player has a uique sound when they hit a show-flake, so the more poeple play, the more complex the music becomes.
This is what the software "sees" through the kinects eye:
you can download the windows version from here: download snow bells for windows but first you must install the kinect drivers for windows: download kinect driver click downloads and run SensorKinect-Win32-.....exe from the "Bin" folder.