Kimbal Musk started PayPal with his brother Elon, then decided to go to culinary school and open a restaurant in Boulder. The results speak for themselves: Musk might be better working in a kitchen than he is at a tech startup. Since opening The Kitchen in 2004, he's opened an upstairs cocktail lounge and a pub next door (aptly named [Upstairs] and [Next Door]), sister restaurants in Denver and Fort Collins, and a nonprofit that is planning to build 180 learning gardens at schools around the country.