You're probably familiar with the card-game "War" in which each person in the game turns over the top card from his or her portion of cards, and the highest number takes all.
In this new version, however, each person turns over two cards, subtracts the smallest from the largest, and the lowest answer wins the cards. If there's a tie, continue as for "War", each person placing three more cards face down and then two more cards face up. These two cards are subtracted, as earlier, and the lowest answer wins all the cards on the table. The game continues until one person wins all the cards or until a time limit is reached whereupon the person with the most cards wins.
Have fun trying for low answers!