Bioculus is a site devoted to life simulations of various sorts. Current offerings, in order of recency, are:
An update on a classic boom-bust cycle of predator and prey dynamics, in big screen glory. Eventually the plants always win.
Light, nutrients, and cellular automata! This is a primitive early draft of a genetic adaptation system intended as the framework of a self-authoring programming language of life. It's not there yet, but it can be pretty.