Any game has versions that manipulate its rules and bend them, etc to create similar games. For example, I heard that in Cuba they sometimes play with the bases in reverse (you run to third base first...). You can play many games around the basket with a basketball, like one we call 'clock' in which you start right below the basket and move away trying to score from around the basket; everytime you miss your opponents gets his/her turn. In chess you have piece-passing, two players against two players; each partner with different-coloured pieces; everytime you get a piece your partner can put that piece up on his board (not doing check) and that eats up one turn. You have 'Kamikaze' chess where a piece that 'eats' another dissappears with it from the board. And 'nom-nom' (name in English by me) where everytime you can 'eat' a piece you are obliged to, and the player who's left with no pieces wins. You can play bridge 'backwards' like trying NOT to make any trick. This was called 'Nulos' in Spanish. So instead of 1NT where you have to make 7 tricks you played 1 Nulo and you had to make 6 (or less) tricks. 7 Nulos meant you had to make 0 tricks; interesting, right? I kinda made one up which I might describe later, do you know of any other bridge 'versions'?