Mao is a particularly interesting variation on chess where one plays with cards rather then a board, all the rules are secret, people need to figure them out by playing often causing complete anarachy
Mao is a particularly interesting variation on chess where one plays with cards rather then a board, all the rules are secret, people need to figure them out by playing often causing complete anarachy

Mao (card game) - Wikipedia

Uno is based on an open source card game.