Rock–paper–scissors
Sportsmen often use RPS (both officially and unofficially, in place of a coin toss) to decide on opening plays. Similarly, uncertain calls, or even the whole game in case of rain, may be so decided. It is also often used as a method for creating appropriately non-biased random results in live action role-playing games, as it requires no equipment. It is also used in some gambling sites as a form of novelty betting.