Drinkers can enjoy a spot of simulated skiing or extinguish some virtual flames while relieving themselves at The Exhibit bar in Balham, south London.
High-tech sensors detect the direction of urine and translate it into action on a 12-inch screen above every urinal.
By aiming carefully while spending a penny, users can guide a skier off piste or put out a raging inferno during their 60-second toilet trip.
There is also a general knowledge quiz called Clever Dick, in which players must pee in the right direction to select their answers.
When their game is over, players are given a code which they can enter into a website to join online leaderboards.
Developed in Britain after three years of research, it is hoped the world-first system will make money for bar owners through advertising.
Designer Gordon MacSween said: "We weren't sure how people would react, but on the first night after we installed it, a group of America servicemen were in the bar.
"I heard one of them coming out of the toilet, high-fiving his mate saying, 'Twelve!'
"His pals were saying 'No way dude!' and going off to play and compete, and I thought, this is good.
"Because of where it is, and you've got a minute of a guy's time, it's a great time to put messages in front of him.
"We've already carried adverts for products whose sales have gone up by 40 and 50 per cent, so they are very keen to use it as a promotional tool."
He added: "Because people are having a laugh, there's a lot less vandalism — people tend to get less angry.
"During testing, we tended to drink a lot of water so that we could play it more often."
The system was trialled at a bar in Cambridge before opening at The Exhibit in London this weekend.
Bar owner Drew Weatherhead said: "Hopefully it will bring people in and they will start competing for high scores."
It comes five years after Nintendo wowed the world with motion-controlled gaming and their pioneering games console — the Wii.
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