Spore has been in development (and eagerly anticipated) for quite a while now. A strange mix of various types of games, it’s going to appeal to a lot of people. The idea that you can design a species from basic DNA and watch it progress all the way up to being a galactic civilization which interacts with tens of thousands of other player created species has got to make it popular. Assuming they do it right of course. It could just be a massive disappointment much in the way the novelty of having my own creature to train in Black and White wore off when I found he wasn’t really that intelligent. You’d spend ages slapping the thing around and making you watch as you threw fireballs and he’d forget everything you’d taught him 5 minutes later.
If you’d like a taster of Spore tho, check out the creature creator demo.