One man's concerns about the impact a large house has on the environment begat his building and living in a house just 100 square feet. Tumbleweed Tiny House Company is Jay Shafer's idea turned reality. The company builds very small, ready-made, portable houses that can be sent to buyers anywhere. It also sells plans for 16 designs. On the site, you can even watch a video of Shafer as he shows viewers around his tiny house. He writes, "My houses have met all of my domestic needs without demanding much in return. The simple, slower lifestyle my homes have afforded is a luxury for which I am continually grateful." Makes you stop and think about all the unused space in your own home.