Mac: You know the movie version of the future where instead of real windows, we've got virtual ones that offer beautiful views of anything we want? Application Winscape pairs your Wiimote with a flat panel TV (or two) to do just that.
It's a seriously geeky project, and it's one that would require a pretty big commitment, but the results, which you can see in the video above, are actually incredibly impressive. The app is free to try, and costs $10 if you want to stick with it after 30 runs.
Hit up the Winscape homepage for more details on this crazy but cool project (including how they built it). You'd be crazy to replace an actual view with a virtual one, but this seems like the perfect (if impractical) project for a window-less room—if you're sitting on a pile of cash, that is.