Go Fish
If the other player does not have the card, then they say "Go Fish", and the player that asked takes a card from the deck and the next player goes.  If a player has no cards when it is time for him to go, then he just takes a card from the deck and the next player goes.  If there are no cards in the deck and the player has no cards, then that player does not get to go.  The game ends when all the cards are face up in pairs.  The winner is the player with the most pairs.