Ithaa Not housing per se, but still interesting.

"Ithaa, which means pearl in Dhivehi, is the world's first-ever undersea restaurant, secured five meters below sea level, at Rangali Island of Hilton Maldives Resort & Spa. The five- by nine-meter restaurant has a capacity of 14 people and is encased in a transparent acrylic roof offering 270° of panoramic view to its customers."

I mostly like it because it reminds me of the Isaac Asimov short story "Waterclap".

http://en.wikipedia.org/wiki/Ithaa  ¶ 10:35 PM