The Zoo is a little project I hacked out one afternoon after a conversation about supercomputers breaking the petaflop barrier compared with mouse brain performance benchmarks, leading to the obvious inevitable SkyNet debacle. Again. I ended up temporarily losing interest in the project long before it got as involved/detailed as I wanted, which probably worked out for the best for the future of humanity. ;)

version 2:
each circle represents one animal in the "zoo".

The animals all have random behaviors, like eat, sleep, walk, or reproduce, which they execute in order. They will become more hungry and tired as time goes on, and can counter it with eating or sleeping. The animal will become more red the hungrier they get, or more blue the more tired they get. Being hungry or tired adversely impacts their health, which will eventually kill them. It also makes them less likely to reproduce succesfully if/when they even try. You can see details about the animal by clicking on them.

If/when an animal succesfully reproduces, they make another new animal that is 'based' on them, IE it starts with almost identical behaviors, with a small chance of minor tweaks and changes.

The idea here is that eventually the proper balance of behaviors will be rewarded with continuation of the species, although in this simulation, unfit species weed themselves out pretty rapidly (say, species that never eat, or sleep, or reproduce).

you can start/stop the simulation with the start button.
you can 'cull' the herd with the cull button, which kills the hungriest/most-fatigued animals.
you can change the speed of the sim with the +/- buttons
you can throw new animals into the zoo with the "more animal" button