Car Trumps is a Windows Phone 8 example game, based on a well-known children's card game. Basically the aim of the game is to select one property from a card in your hand (e.g., the car's top speed) which you think can beat the opponent's matching property. This is a two player game, and requires two phones with NFC support.
The game starts when the players touch the phones together. A random hand is given to both players from the deck. Both players select a card from their decks. Then the other one of the players has to choose a property to compare. The comparison is executed by touching the devices together. The winner gets the opponent's losing card. The game ends when either player runs out of cards.