There is a great, low-cost program online that is more fun than any video game. Spore Creations by Electronic Arts allows one to create new beasties or just to recreate current or extinct ones. Of course, I had to make a penguin, but there's more to the program than mere aesthetics. The creator is compelled to think about what goes into the construction of said beasties. For example, the creator must determine how many vertebrae an animal should have or where to put the mouth (depending on how the creature feeds) or spacing of the eyes (is the creature given forward eyes or eyes on each side of the head--then to think why are those eyes placed just so).
The next step is to play around with evolution--what will the creature look like in, say, the next 10K years. The trick is to either improve or remove qualities already present within the creature. I can see this little program having much potential in provoking students to think beyond the game and into reality.
And so, here I present my own little Emperor Penguin. Enjoy!
(Link to Spore's website)