The Comploo tea house from the Japanese design firm Bakoko uses heat from decomposing compost to keep you toasty. Although living in a Comploo keeps your heating bill down, expect your eggshell and banana peel bill to skyrocket.
The Comploo warms visitors thanks to its circular structure of compost bins - the Comploo's owners fill the bins, which allows the naturally decaying organic material to warm the enclosed space. With enough compost, the Comploo can reach up to 120 degrees Fahrenheit.
I love this little house. It's shaped like a UFO, its heating system appeals to me on an environmental level, and its name appeals to me on an unabashedly fourth-grade level.