I am not the biggest gamer, by far. But recently I found out about a game called EVO : The Search For Eden, for the SNES. I decided I would take a look at the prices for this bad boy and.....$50 was the lowest I found.....

So I went and downloaded an emulator =P.

Basically in this game you start out as a fish thing and eat stuff and choose what parts of your body you want to evolve. Its really cool, and I love it.
A video

By the end of the game theres lots of stuff you can become, even a human.