Crowds and other forms of flock-like group motion are modeled with interacting particle systems. These multi-agent simulations are computationally expensive because each agent must identify its nearest neighbors. Time to run the simple implementation grows as the square of the number of agents, so large groups can be prohibitively expensive. This lecture will describe experiments running crowd/flock simulations with thousands of individuals at 60 frames per second on the PLAYSTATION3. It will discuss how a traditional crowd system can be recast to map efficiently onto the Cell architecture of the PS3. The lecture will include implementation details and live demos will be shown.