Poker is a card game that can be played between 2 or more players. It is usually played with chips that represent money, and the object of the game is to win the pot (the sum of all bets placed during a deal). There are many different variations of poker, but most of them share certain core principles.
Each player is dealt 2 cards face down (hidden from other players) which are called their hole or pocket cards. A round of betting follows, with each player placing chips into the pot based on the rules of the particular variant being played. Once the pre-flop betting phase is complete, 3 more cards are dealt face up to the center of the table, which are called the flop. This initiates another betting phase, with the player to the left of the big blind taking the first action.
The rest of the game is a series of rounds of betting, with each player revealing their cards in turn and potentially raising or folding their hand depending on the circumstances. A standard poker hand consists of five cards, and the value of each hand is determined by its mathematical frequency; for example, four of a kind is more valuable than a pair. If two or more players have identical hands, ties are broken by the highest unmatched card or secondary pairs (in a full house).
While there is some degree of luck involved in poker, the betting component lends the game quite a bit of skill and psychology. It is this combination of risk and reward that draws people to the game, from teetotalers like Dale Carnegie who play for a little fun to professional players like Durrrr or Isildur1 who compete in massive tournaments for ludicrous amounts of money.