Many contemporary variations of rummy games are based on the original games. Gin Rummy is one of the most well-known varieties; it gained popularity in the early 1videobuddy new version900s. Gin Rummy is a game in which two players compete to form sets and runs from their hands while attempting to "knock" before the other player does. In order to prevent giving their opponent an advantage, players must choose when to knock and how to use their discards. This is what makes the game so strategically complex.