Integer Card Game

I borrowed this one from a colleague and I've used it successfully for years.  I use it right after I review adding integers in Algebra 1.  The game is modeled after the classic game "War".  The students get in groups of two and each group gets a deck of playing cards.  The cards are divided in half between the two players and they each put their stack face down.  Each student turns over two cards and adds them together.  The student with the greater sum gets to keep all four cards.  Assign red to be negative and black to be positive.  Aces are worth one, number cards are worth their value, jacks are 11, queens are 12 and kings are 13.  There is usually a happy feeling in the room when they are playing this.