Memory is a card game designed for two people, although single player modes are available. Cards are laid out in a grid face down, and players take turns flipping pairs of cards over. On each turn, the player will first turn one card over, then a second. If the two cards match, the player scores one point, the two cards are removed from the game, and the player gets another turn. If they do not match, the cards are turned back over.
The object is to match more pairs of cards than the opposing player. (One point is scored for each matched pair, and the player with the highest score after all cards have been matched wins.) When cards are turned over, it is important to remember where they are for when the matching card is turned up later in the game.
In this online version of memory, there are twelve unique pairs of cards, making 24 cards total.
Source: The Game Website.