Eddie's Room - Munster House

Eddie's Room has a trapdoor at the bottom. His babysitter slips him a glass of milk in the very first episode.

 Eddie's room changes a lot. Apparently sometimes his room was cleaner than others. He and Herman sit on a set of stairs often for their little father and son chats. It isnt easy to see, but the stairs lead to a door and apparently through that door is where his sleeping "box" is. You can see the door in the picture that is 18th down from here. It is the picture where Herman has fallen down in a dust cloud.

Here is the door at the top of the stairs.