Spore
This game won "Best in Show" in E3 2005.Basically, it lets you play god. The player creates a creature and follows it through its different life cycles and evolution. Or so I gather.
edit: I should probably mention this is just a video of the game shouldn't I? Folks - this is just a video of a guy showing the features of the game.
Here's an explanatory video Yuval sent me. Give it a look - the game looks amazing. A kind of really cool civilization mixed with sim city.
[Video]
[Game Site]
