Samsung just started showing off a 19-inch AMOLED screen that's 30% transparent, allowing you to see right through it. It's super thin and looks straight out of the future.
Of course, no one would actually want a TV that was transparent like this. It certainly doesn't do the picture quality any favors. But for a neat trick that shows off all the stuff their researchers are working on, it sure is impressive. And really, I can imagine this sort of thing being used in public places for advertising and that sort of thing in the not-too-distant future. But unless there's a way to turn that transparency on and off easily, don't look for this to replace anything in your living room.