6. Bastian Lehmann

CEO of Postmates

Lehmann is a huge fan of retro video games. His startup Postmates is solving one of the most important problems in technology right now: same-day deliveries, which even company like Amazon craves for. The latest service from the company is "get it now," in which Postmates couriers will buy anything within San Francisco and deliver it to you in an hour.

5. Aaron Levie

CEO of Box

Box is another red-hot enterprise startup that has put Aaron Levie in the billion-dollar startup CEO club. He just finished raising a huge round of funding that valued the company at more than $1 billion.

It's an online storage service like Dropbox and Google Drive. But it focuses on providing services to large businesses instead of consumers.

Levie carries an electric orange and a deck of cards for a magic trick. He is one of the most fun CEOs in Silicon Valley and is also one of the most hard-working.