The only thing we knew about Spencer Harper before we barraged him with personal questions is that he takes sustainable living very seriously. Instead of paying for a resource-guzzling house or apartment, Spencer lives in a solar-powered van -- complete with a kitchen, bed, and desk. The entire vehicle is about the size of the conference room. And since his home truly is mobile, he can split at a moment's notice and go places that inspire is creativity, namely, some of the country's most amazing parks and wilderness. He also works at Google.