A game of two; The last person to remove stone(s) wins. A player can only remove a min of 1 and a max of 3 stones at a time.
Actually there's a strategy for the person who starts the game to always will. Plan your move such that the other person always gets 12, 8, 4 stones with him on his turn. This is an easy, quick-ending and fun game try it out with your friends.