Rummy is a popular card game that involves matching cards of the same rank or sequence. Players aim to form sets or runs, which are specific combinations of cards. The game can be played with two or more players and typically uses a standard deck of 52 cards. There are many variations of Rummy, including Gin Rummy and Indian Rummy, each with its own rules and scoring systems. The objective is to be the first to "go out" by laying down all your cards in valid combinations, while also trying to minimize the points in your hand if another player goes out first.