Ashton Kutcher

I think Ryan Gosling is a really great actor who's meticulous about his work. And I'd love to have the guts that Johnny Depp has to actually go outside the box on a character. When he plays a character, he plays it in a way that nobody else would.

Anyone who wants to be an entrepreneur like someone else is actually looking in the wrong direction. You don't look out for inspiration, you look in. You have to ask yourself how can I be better today, at solving the problem I am trying to solve for my company. I wouldn't encourage anyone to be like me. Just be like you.

Supplying fuel for a Mars expedition from the lunar surface is often suggested, but it's hard to make it pay off - Moon bases are expensive, and just buying more rockets to launch fuel from Earth is relatively cheap.