A bedroom in a (unused) sewer pipe.

[BC Guy]

http://www.amusingplanet.com/2011/08/das-park-hotel-built-from-giant-sewage.html
You could use these as guest cottages.<g>

 

[my_vantasy]

It's not often I see "bedroom" and "sewer pipe" in the same sentence, so I had to look.

Now that's creative repurposing!

 

[Patrick46]

at least you'll be safe if a big bomb hits nearby!