Bongo Pongo is a custom version of Pong, which lets players use a platform-type device to control movement. Video demonstration after the break.

For $6 I was able to get a short length of 5″ PVC pipe and a piece of wood (which I later replaced with the skateboard deck seen in the video below), and some small metal tubes to use for the tilt activated switches. The total expenditure was less than $20 for enough equipment to make a board for each player

[via HackedGadgets]