In his book Self-Organization and the City, Juval Portugali describes how, in the past sixty years, our conceptualization of cities has shifted from a portrayal as isolated, stable and transparent systems, into open, self-organizing and complex systems, and how the role of the planner has turned from that of an engineer who masters these systems into that of, at best, simply observers and participants. Though Portugali's vision of the role of the planner might be too polemic, what is indeed an issue is that planners are in need of new tools that will enable them to be more process orientated, more geared towards communication, and encouraging of the involvement of multiple stakeholders, etc. Computer simulation models meet these requirements, but although they have indeed been adopted in planning practice, they have not become an indispensable piece of equipment. A very different story emerges from the gaming industry where, for more than twenty years, computer games have continued to attract millions of players, and have even entered classrooms and planning practices. Not only do these games look increasingly realistic but the behaviour of the characters within them has grown ever closer to resembling actual behaviour, to the extent that some commentators have even started to propose that planners should turn into gamers. Does this make sense, or is it still a bridge too far? In the search for an answer, this paper will critically analyse two computer games: SimCity, which is a classic strategy game, and Second Life, an increasingly popular social virtual world. I will make a number of suggestions as to how these games could be upgraded into planning simulation models.In his book Self-Organization and the City, Juval Portugali (2000) sketches a condensed history of what he refers to as prototype urbanisms, namely metaphors that capture how cities were perceived and imagined over the last century. He starts with Von Thü nen's "isolated city state", and ends with his own "hypermodern self-organizing city". In the sixty years between these two prototypes, the conceptualization of the city has shifted from that of an isolated, stable and transparent system, into an open, self-organizing and complex system. What Portugali claims and illustrates is that, in spite of being open and complex, cities do exhibit essential features of self-organization (e.g. social segregation, congestion) or, as Jane Jacobs (1961) argued half a century earlier, cities are