On the net...
Zero sum games:
Chess, for example, is a zero-sum game: it is impossible for both players to win (or to lose).
Monopoly (if it is not played with the intention of having just one winner) on the other hand, is a non-zero-sum game: all participants can win property from the "bank". In principle, in monopoly, two players could reach an agreement and help each other in gathering a maximum amount from the bank. That is not really the intention of the game, but I hope I have made the distinction clear: in non-zero-sum games the total amount gained is variable, and so both players may win (or lose). When they can both win by cooperating in some way, we might say that their cooperation creates a synergy.
The casino is the "bank" as above? Or it is just another player in the game?