1. Interactive entertainment apparatus comprising: a first data store containing data defining a virtual environment; a second data store containing data defining the external appearance of a plurality of characters; a third store holding a population of rules which, when compiled, comprise a plurality of interacting agents governing the actions of respective ones of said characters; and a data processor arranged to access the first, second and third stores and generate an image of the virtual environment and characters therein from a first viewpoint at a predetermined position and orientation within the virtual environment, characterised by: monitoring means coupled to periodically monitor at least one compiled behaviour per character agent and the respective locations within the virtual environment of each of the characters; cluster generation means coupled with the monitoring means and arranged to generate clusters, each cluster comprising one or a plurality of adjacent characters within the virtual environment, in accordance with a predetermined clustering criteria and to generate a respective cluster value derived from the current setting or settings of the monitored behaviours within that cluster; and selection means arranged to select one cluster in dependence on the derived cluster values and determine the location of that cluster within the virtual environment, the data processor being arranged to move the position and orientation from the first viewpoint to a further viewpoint overlooking the cluster.