Checkers, known as draughts in British English, is a two-player board game played on a square board. The number of squares on the board varies - in the United States, it is often eight squares by eight squares; in other countries, the board may be ten squares by ten squares or twelve squares by twelve squares. For the purpose of this article, checkers will refer to the 8x8 version.
One side is red, the other is white, and this term applies even if the pieces of the player with the "white" pieces are black, as is often the case, especially with cheap plastic sets. 
Checkers move forward and diagonally, unless they are kings, in which they move diagonally either forward or diagonally. Only half of the squares are ever used, because a checker can never legally change colors due to its diagonal move, similar to the bishop in chess. Checkers capture opposing checkers by "jumping" over them, if they can move over them onto an empty square past the diagonally adjacent checker. Double, triple, or even more jumps are possible in one turn, as long as it is the same piece doing it. If a player can legally jump, he or she must do so.
If a checker advances all the way to the other side of the board, it becomes a king, and can move forward or backwards.
A player wins the game if he or she captures all of his or her opponent's pieces, or if the opponent has no legal move.
In 2007, a computer called Chinook ultra-weakly solved checkers on an 8x8 board, that is, determined that the game is a draw with best play, but as of yet, no specific algorithm for bringing about this result has been brought forward.  In the near future, this may change - computers are working on producing an algorithm. In this case, the game would be weakly solved.