A casino is a place where people can gamble by placing bets against the house. Casinos offer a wide variety of games that are legal in some places and banned in others. They also provide other luxuries such as restaurants, free drinks and stage shows to attract gamblers.

A large number of people visit casinos to gamble. Some casinos are massive resorts like the one in Las Vegas, and some are smaller businesses defined more by the types of gambling they offer than by glitz and glamour. In general, casino visitors tend to be younger and female and to come from households with above-average incomes. In 2008, 24% of American adults reported visiting a casino in the previous year.

Slot machines are the economic mainstay of many casinos, generating more than half their income. They are simple to operate: a player puts in money, pulls a lever or pushes a button, and watches as bands of colored shapes roll on reels (actual physical reels or video representations). The machine stops when the winning combination is formed. In the United States, the average slot machine return is 94 percent.

To encourage gamblers to play, casinos may offer comps. These are free goods and services that are given to a patron in exchange for the amount of time they spend at the casino and the size of their bets. For example, high-stakes gamblers can receive free hotel rooms, dinners, show tickets or even airline tickets if they spend a lot of money at the casino.