This is a video of Youtuber Frank Gombault demonstrating the flatscreen television he installed in a sliding pocket door. The television is on a hinged arm so it can be pulled out of the door and the door almost closed while the TV is in use. It can also be swiveled for viewing from either room. Eventually though, it will get stuck inside the wall and be destroyed.
Keep going for the video demo.
Thanks to Carmen, who watches television the much more frugal way: on a neighbor's TV with binoculars.