Odd houses

From Recycled homes:

In 1994, a hairstylist in Benoit, Miss., named JoAnn Ussery lost her 1,400-square-foot house to an ice storm. Ussery had a relative who worked in aviation, and the two came up with the idea to salvage a Continental Airlines 727. It cost her $2,000 to buy the plane, $4,000 to move it to her lakeside lot, and about $24,000 to outfit it comfortably. Ussery did much of the renovation herself, and took advantage of the ample windows and storage bins, as well as the lavatory. Ussery told reporters that she was mainly attracted to the idea because of the plane's low cost and durability.

In the 1920s, a Southern California architect and recycler by the name of Miles Minor Kellogg built two distinctive homes in the shape of boats, out of bits of material he found locally.

From Cave houses:

Tucked into a 17,000-square-foot hole left by a sandstone mine in Festus, Mo., is the spacious, beautiful home of William "Curt" Sleeper, his wife, Deborah, and their three kids. The Sleepers almost lost their unique three-bedroom house to foreclosure, but they recently received backing from a private investor after media exposure.
...
He says he doesn't need to heat or cool the home because the natural insulation of the cave walls keeps the inside air 65 to 70 degrees year-round. The Sleepers constructed the façade of their dwelling out of 300 sliding glass doors purchased from a local resale shop. "I stripped the aluminum and resold it to the local recycle center," Sleeper adds. "We pull more than 100 gallons of water per day from the air with our dehumidifiers and then pump that outside to water our gardens and feed chickens."

For centuries, people lived in homes carved into the soft sandstone of the Kinver Edge escarpment, on the border of Staffordshire and Worcestershire in England. The most famous cluster was under Holy Austin Rock, which at one time served as a hermitage. The last cave dwellers moved out in the 1950s, but the site is preserved by the National Trust, which has restored some of the cave houses to the Victorian period.

Some observers have wondered if the cave homes and their small cottage gardens had inspired J.R.R. Tolkien in his imaginings of hobbits, since he grew up nearby.