Poker tournaments often consist of several people.  These tournaments can be played for fun between friends, with little money exchanging hands.  Professional poker players also partake in tournaments and can win and lose very large sums of money.
During a professional poker tournament, players continue play until they are out of money.  The game keeps going until there is one person left who is declared the winner.  These tournaments can take hours.  Professional poker players can have sponsors who help supply the money backing the play.
Poker is growing in popularity and professional poker tournaments are often televised.  There are names for annual tournaments such as the World Series of Poker and the World Poker Tour.  Such big name tournaments often take place in Las Vegas, as it is considered the gambling epicenter of the U.S.  Players show stoic determination and have mastered the art of hiding emotion so as not to give away what cards are held in hand.  Some players wear sunglasses or hats to help hide their expressions.
If you are not interested in playing poker professionally, there are several online options.  Many gaming sites offer ongoing poker games that you may enter in to or exit out of at will.  Most of these sites require that you are of the legal gambling age, which is 18 in most areas.  While these online tournaments may seem more like arcade games, they can be costly.  You are usually asked to enter a credit card number and your poker winnings and debts are debited accordingly.  Online poker has aided in racking up large sums of debt for numerous people.  Playing online makes poker seem like any other free game and since players don’t visually see money exchanging hands, it can be difficult to know when to stop playing.