In 2008, Chesky and his roommate Joe Gebbia, Rhode Island School of Design alums living in San Francisco who were short on rent, decided to blow up some air mattresses and charge travelers coming to town for a place to crash. A revolution in couch surfing was born. Four years later Airbnb, the site they created -- along with their third co-founder, Nathan Blecharczyk -- is a massive platform for shelter-sharing and a poster child for the sharing economy. The company now has 400 employees and at presstime was said to be raising a third round of funding at a valuation of $2 billion. Gebbia focuses on user experience, and Blecharczyk is CTO, but Chesky runs the show, getting out in front of issues like hotel occupancy taxes and increasingly making the rounds at mogul confabs. Describing the past four years in one word, he says: "Surreal." Tambourine man: Chesky is a huge Dylan fan. --Leigh Gallagher