Man, artificial life gets me hot. Did I just say that out loud?
Gene Pool is a cute little a-life sim in which “swimbots” compete for mates and food. Each swimbot is made of small segments, which are used to propel it across the primordial soup. Swimbots which are more “attractive” (determined by a number of factors, including segment color), can swim faster, or develop independent video games get to propagate their genes over their uglier, slower neighbors.
Not really a game per se, but it’s fun. You can pick up swimbots and help/hurt them. Gene Pool also has a number of parameters you can set to change the way your swimbots evolve, such as attractiveness.
Pictured at left: two swimmers ’bout to bump uglies (or, in this case, little pink arrows).
(Source: Alehkhs, via Puppy Buckets)