Secret Rooms

This morning my wife and I got on the topic of architecture. Not that either of us has any experience with such, but she started imagining how our apartment could be different (moving the living room closet to the hall, for example). So I began thinking about building a house. I don't know the first thing about building a house, but I wondered about secret rooms and hidden passages. Maybe I'm creating more of a castle in my head than a house, but I can dream, right?

She and I talked about such secret rooms, and she thought it was a bad idea. I replied, "How cool would it be to move into a house and, after living there a while, to find a secret room, especially one that didn't have any dead bodies in it?" The lack of corpses is very appealing to me. So I wondered about what I would do to such a room if I had (a) built it, (b) sold the house and moved on, and (c) expected someone else to find that room eventually. Here's what I've come up with:

1. Create a "Narnia Space" – Make the room look like you've gone to another world entirely.
2. Creepy Halloween Room – Scare the bejeebers out of the poor soul who stumbles upon this room. I'd rather not reveal how morbid my sense of imagination is here, so I'll leave this one up to your minds.
3. Secret Agent/Superhero – Make it look like James Bond, Tony Stark, or Ezio Auditore da Firenze hid their cool stuff there.
4. Beanbags – Beanbags everywhere. That's it.
5. Time Machine – Collect (or recreate) artifacts from history and make myself look like a time-traveller. This could also be considered a variant of Narnia Space, but within Earth's history rather than Narnia's.
6. Hidden Library – Stacks of books from floor to ceiling, most of which would really just be worthless, but enough so that the next person would think they'd found Alexandria.
7. Alchemy Lab – Produce ruined attempts to turn other metals into gold. Maybe one success. Include journals detailing the history of attempts and processes used.
8. Toy House of Horror – A room of terrifying toys, like Furbies or Elf on a Shelf. The things that creep me out are those dolls whose eyelids were weighted and they opened and closed based on their body angle. *shiver*
9. Massive Aquarium – Imagine it: you walk into a room you didn't know was there, and the first thing you see is a shark behind (what you hope is) bullet-proof glass. Awesomeness.
10. Nothing – They walk in, and either think, "Hey, a secret room. Neat-o," or "Why is this here? Why is this here?!?" (This is where you imagine me doing an evil villain laugh.)

What would you do with a secret room that you had to leave behind? An elaborate prank, or an awesome gift? Let me know in the comments!