Poker is an internationally popular card game played in many different places including private homes, clubs, casinos and over the Internet. It is a game in which players combine their own hole cards with the community cards to form a hand. Each player can play with one or both hole cards, or no hole cards (play the board). The game has a long history and is widely considered to be the national card game of the United States. Its play and jargon permeate American culture.
A number of variants of the game have evolved over time, and many different rules are in use today. It is most commonly played with a standard 53-card pack with the joker included as the wild card. This card can only be used to complete a royal flush, straight, four of a kind, or certain special hands.
In the case of poker tournaments there are a number of organizations that manage the rules. The most notable is the Professional Tournament Directors Association, which has over 2,500 members in 63 countries around the world. The organization meets every two years to review new poker rules and standardize them across the globe.
A round disc called the dealer button is passed clockwise around the table each hand to indicate who should act as the nominal dealer for betting purposes. In the majority of commercial environments that host poker games, such as clubs, casinos and online poker rooms, a professional dealer is employed to take on this role.