The Ping Pong Door, from designer Tobias Franzel, is a door with a middle section that flips out to reveal a ping pong table. It's not regulation. The playfield is small, the net is plastic, and one side of your kitchen door is green with a line down the middle. If you can get past those things, then maybe this door is for you. It's not for me though. The only reason I posted it is because that leggy brunette that looks like a boy is confusing my penis in the most delightful way.
Ping Pong From A Doorway [yankodesign]