You know, speaking of Bob, one thing I've been meaning to experiment with is a Minecraft-based desktop UI.
I'm completely serious. Minecraft is relatively intuitive, the space is completely malleable, human minds are already tuned to navigating such spaces...
There's even some precedent in Bob and PSDoom, among others.
A couple months ago, after 5-6 years of not playing it, I installed Minecraft again fiddled around for a week or so. It took me a good day or two to get a solid grasp on all the UI changes that had happened since I stopped playing. I had to get on Google just to figure out how to eat.
I agree that it's relatively intuitive. Emphasis on the "relatively" part - I'm thinking here that it's intuitive compared to the UX changes and kippleization that iOS, Google web apps, things like that have undergone over the same time period. That's not exactly a high bar to clear.
Way to throw Bob under the bus...