The card game rummy has historical roots that stretch back to the 1800s. Though its exact origins are unknown, a combination of games, such as rummy yesMahjong & Conquian, is believed to have inspired it. Due to the popularity of rummy in the US and Europe, several variations have been created, including Gin Rummy, Indian Rummy, & Kalooki. Cash games of rummy, in which players wager money on each other, have existed since the 1920s.