I ran across a neat “educational” game today – WolfQuest. I found a link to it from a news article at the NSF: Real-World Lessons in Virtual World.
In the game, you play a wolf in Yellowstone – they drop you into a 3d environment and you run around as a wolf, hunting, looking for a mate, and generally surviving. The article included a video of the gameplay so you can get a sense of what you see.
There is a single and multiplayer mode, and it runs on Mac and Win32 – it’s a pretty cool setup.