About.com provides instructions on how to play basic Mancala. Variants of basic game play using the same board and stones are available on the BGamers website.
Mancala is a simple game that requires a game board with 12 pits, one store for each player on opposite sides of the board, and 48 marbles or stones. Players distribute four stones into each pit and take turns removing stones from a pit on their side to distribute counter-clockwise around the board. One stone is dropped into every pit until the player runs out of stones. If the player passes her store, she deposits one stone, if she passes her opponent's store she skips over it and keeps moving around the board. The player with the most stones in her store at the end of the game, wins.
Mancala is an ancient game with many variations that change the gameplay while using the same basic pieces.