A showcase of Darwinian evolution
With DarwinBots you can get a better sense of how evolution actually works. This top down game, offers you a map, in which a number of bots mess about. They are coded, genetically to thrive, consume food and reproduce. They share very similar characteristics, physically; however, their autonomous behavior is dictated by how well their senses work. Thus, as you'll see, over a few generations, the bots that weren't as fast or as smart in reading their environments will no longer be able to reproduce, or will have gotten themselves killed. Thus, simply and elegantly, the game simulates natural selection. The cool thing is that all robots have a DNA sequence, a number of memory inputs that get passed from generation to generation, and so, mutation, given that each new bots shares DNA with both their progenitors, can change over time. It's a valuable game in that it puts a working, no strings attached, no preprogrammed behavioral game in front of you. You can also go about and change certain parameters of the simulation, but most of the fun of it all is looking at it and seeing the bots interact with eachother, with the environment and more or less slowly changing and demonstrating evolution. If you'd like to download a similar game - Gene Pool is just as good an alternative, though one that doesn't make a case for evolution as DarwinBots does.