Not really a variant, but a different way of playing. You need three people to participate.
The players are seated in a triangle with a Goban between every pair, and each person plays the other two, so you have three simultaneous games going on. Best played on 9x9 (with the pieces of a broken cardboard goban) otherwise the table you need is very big!
- Play with four people: three in a large triangle and the fourth player in the middle on a revolving chair. The game could possibly be played on any planar graph (a 19x19 grid would be very interesting to watch but you'd need a airplane hangar :-)
- You can keep the pace down by first playing in the A-B game, then B-C and then C-A.
- For weaker players it is a good idea to somehow mark the last move in each game by playing with a different type of stone (color/size) and replacing that by a normal one after the opponent makes his move.