Like the memory game. Win pairs of cards by turning over two and matching their number.
A standard deck of cards
Shuffle the cards and lay them face down in 4 rows of 13 cards. (When playing with younger players you may want to use fewer cards.) The first player turns over any two cards. If they match, regardless of suit, he removes them and tries again. If they don't, the cards get flipped back over and the next player tries for a match. She can also turn over any two cards (including those turned over by other players).
Remind players to pay careful attention to the cards that others turn over. The information will come in handy when they look for their matching cards. Play continues in this way until all the cards have been removed. Then the players count their cards. The one with the most is the winner.
To make the game easier for younger children, remove all the cards from two suits, leaving two left. Fewer cards on the table make it easier to remember what was where.
To make the game more challenging, the players have to match rank and color. For example, the two of spades matches the two of clubs, and the two of hearts matches the two of diamonds.