On a suggestion from Ubuntu Forums, I decided to give ReactOS a spin. ReactOS is currently unique in the world of free software for being an attempt to reverse-engineer, in a "clean room" environment, a binary compatible operating system to Microsoft Windows. No, it's not Linux with a MS Windows-like shell; it's a complete kernel written from scratch, but using Wine for its userland application space.
As you can see from the screen above, they actually have gotten somewhere. Unfortunately, ReactOS isn't quite stable enough to be of much use in a production environment.
One thing to say about ReactOS: at only 30MB it's pretty small. Which sort of gets one thinking how much bloat is actually present in the final Windows code. Understood that it doesn't offer full compatibility, but still... Anyway, I ran the installation as a VirtualBox guest, and it was pretty quick.
ReactOS doesn't come with any preloaded applications, but it does let you download them from the web. Staple applications are Abiword, Firefox, and other tools. I only downloaded and tried Firefox 2.0. It had small rendering problems, but otherwise worked.
Honestly, it's been a while since I've used Windows to any great degree but the user interface of ReactOS fairly approximates the experience. As I said, ReactOS is still very much in Alpha, but if it does take off, it'll be something to see.
And, um, yeah: the Blue Screen of Death.