I'm not sure how practical this is, but it's a neat invention nonetheless. A company called Active, Inc. has developed LCDs that turn opaque at the flip of the switch. That means you could stop using your monitor to watch movies or surf the web and turn it into a window, perhaps installed in your home somehow.
While it would be pretty cool to have a window that was also a screen, the lack of a backlight would make the screens usefulness questionable at best. Even lighting is pretty much a necessity in LCD screens, but hey, any advancement is a good advancement I suppose.