The Spore Community Website now offers downloads of ParticleMan, one of the simple, playable prototypes they've built to test subsystems they are incorporating into Spore, EA Maxis' upcoming evolution simulation (thanks Mike Martinez) and Kotaku). Word is: "ParticleMan simulates gravitational attraction between particles in a cloud. This system was used to study such gravitational dynamics as orbits, nebula formation, star formation and particle streams from sources like pulsars and black holes."