I love to find examples of good design that's working for a good cause. In the case of designer Vinay Gupta's Hexayurt, those two elements are definitely present. The Hexayurt is, in Gupta's words, a "microbuilding." Gupta's design is a small, strong, and economic structure that can be erected in about two hours, and is made from easily accessible materials such as insulation board, plastic, and cardboard. The Hexayurt has a high R-value, which means that it is relatively comfortable in high and low temperatures.
Gupta's designs for the Hexayurt are in the public domain, which means that they are available for free download. While the Hexayurt was originally envisioned as a refugee shelter, it's recently gained popularity at campsites at the desert festival Burning Man.
To see a video explaining the Hexayurt,