Spore

Spore isn't due out until September, but the developers have released the Creature Creator for download here recently. People can try the free trial version which has 25% of the build parts, or for $10 they can buy the full version of the creator, though the full game still will not be available for a few months yet when it releases at its normal MSRP of $50. Even the trial version is a download in excess of 200 MB, but if anyone is interested they can pick up either from the official website, Spore.com.

Here is my first creation, built with the limited trial version:


The full game is a lot more than just building your own creatures. You go through different gameplay phases as you begin as a simple, almost single-celled type of life form and evolve up from there. As your creature grows and improves, gameplay will go through changes with it until it becomes an advanced social creature like us humans and even potentially an inter-stellar species. Users can share their creations, and other users' creations can appear in your game world for your creations to interact with, for better or worse. Your creature's success at anything depends on how it is built and it will do the best that it can based on how you built it, and its skills and abilities entirely depend on its construction. This will also influence how it handles encounters with other creatures, including whether it is more diplomatic or war-mongering at the society level.

Here's a shot from earlier stages when you're a smaller, simpler creature:


Farther along, this is a beast with a ways to go yet:


It's a dangerous world out there. Hopefully your creature was built to survive in it.


Evidently, someone went with a more aggressive type of creature:


They don't have to be war-mongers, though:

Hey that looks pretty cool. I might get this when it comes out.

Huh. Looks weird.