I found this online today.
An artist, along with several other artists built a secret apartment in the parking garage of Providence Place Mall, in Providence, RI. They built the apartment in 2003 and were undiscovered for four years! News article
They have a website even: Trummerkind
It's a confusing web page, but there's a ton of stuff on there about the apartment, you just have to explore. Under "The Secret Apartment in the Mall" they have a description of what was behind this plan. And there's a blog with a few posts. Then under "The One" is a real estate ad for the apartment, complete with a list of the "amenities". :p
Maybe they read "From the Mixed-Up Files of Mrs. Basil E. Frankweiler" when they were kids? :)
Obviously the apartment is illegal, but it sounds pretty awesome! They had a china cabinet in there even...
The art this guy and other artists do is interesting too: Tape Art
And does anyone know where my post title is from? Not you, Mom...I know you know it. :)