A
1970s era
tabletop game. Gnip Gnop (
ping pong backwards) was a game with
6 balls in it--3
pink and 3
green). The game play area is split into
halves by a
clear plastic piece with 3 holes, slightly larger than the balls. On each side of the center, a black
plastic bottom sloped down from the center to the edges where there were 3
levers controlled by
paddles outside the game's
plastic cover.
The object was to be a sort of Maxwell's Demon and get all 6 balls on to your opponent's side as quickly as possible. This was no small feat with the small holes, balls flitting about everywhere, knocking in to one another, etc. However, despite that, most games were in fact less than a minute long, allowing for, well, ping-pong style scoring.
Also, made out of polystyrene, the game was incredibly noisy. Wow.
Gnip Gnop was one of the games that I never had (but lusted after insatiably) and had to play at friend's houses. It was only much later I realized the profound thermodynamic overtones of the game play.
It was manufactured by Parker Brothers, who also brought you Monopoly and Risk.
(source: http://www.yesterdayland.com/popopedia/shows/toys/ty1023.php)