A casino is an establishment for certain types of gambling. Most casinos offer a wide range of gambling activities and are often combined with hotels, restaurants, retail shopping, and tourist attractions. In the United States, there are about 1,000 casinos. Most of them are located in Nevada, where the majority of the gambling revenue is generated. Casinos are also found in Atlantic City, New Jersey and on American Indian reservations.

Slot machines generate the largest percentage of the profits for casinos. The game is simple: the player puts in money, pulls a lever or pushes a button, and watches as varying bands of colored shapes roll on a series of reels (actual physical or video). If the right pattern appears, the machine pays out a predetermined amount. The lack of any skill or strategy on the part of the player makes slot games particularly appealing to people with limited spare time.

The casinos rely on a number of security measures to prevent cheating and theft by both patrons and employees. These include video surveillance and rules of conduct. The high amounts of cash involved in gambling make it possible for patrons and staff to be tempted to cheat or steal, either in collusion or independently. For this reason, casinos spend a significant amount of their income on security. Security personnel watch for blatant cheating, such as palming or marking cards, and for betting patterns that suggest that someone is trying to manipulate the game.