A game which is not zero-sum.
For historical and technical reasons, zero-sum games have special status in game theory, but advances in the subject (in particular, by John Nash) have meant that many notions can now be dealt with via a framework of general sum games. For instance, the natural defintion of strategic form games is for an n-player general sum game; the earliest work by Von Neumann now being treated as special cases (fixing the number of players to two, introducing the zero-sum condition, or both). Note, however, that some progress was made towards the analysis of general sum games prior to the development of Nash Equilibria: an n player general sum game in strategic form can be turned into an n+1 player zero-sum game in strategic form.
A coalitional form game is also assumed to be general sum by default- with zero-sum games being a special case of a special case, namely that of constant-sum games.