Hint: Before age 30, the Harvard computer science grad founded two successful companies. One, a software provider for public schools, he sold for $20 million. He's now CEO of the other, which is targeted at reducing home energy consumption by providing users with better data. He caught the environmentalist bug on a yearlong trip where he drove from Antarctica to the southern tip of Chile. Now, according to his company bio, he's on a mission to save "what remains of our natural world."