Moral theorists and game theorists are both interested in situations where rational agents are to constrain their future actions and co-operate with others instead of being free riders. These theorists have constructed a variety of hypothetical games which illuminate this problem of constraint. In this paper, I draw a distinction between like the Newcomb paradox and like Kavka's toxin puzzle, a prisoner's dilemma and Parfit's hitchhiker example. I then employ this distinction to argue that agents who subscribe to the orthodox (...) theory of rationality do significantly better in disposition games than those who subscribe to revisionist theories like David Gauthier's, while revisionist agents do marginally better in behaviour games. I argue that because of agents' ability to manipulate their own weakness of will, orthodox agents do better at all of these games than has previously been thought. And, by elucidating the distinction between behaviour games and disposition games, I uncover the virtues that underlie the success of each theory of rationality. (shrink)