TRING is a variation of Carom Billiards.
It was invented by our Computer Graphics professor Jarek Rossignac.
It is played on a circular pool table with three balls: one red, one green and
one blue. Players take turns and use a billiard cue to strike one of the balls. On each
shot, a different ball is struck, cycling through the three colors. First red, then
green, then blue, red again and so on. Suppose that the red ball is struck with the
cue, if it touches the other two, the player scores one point and plays again, striking
the green ball this time. When the cue ball (the ball struck by the cue) stops before
touching the other two, the next player will play the ball with the next color in the
cycle. First to reach 21 wins.
If you're really interested, download the game