Bill Gates

Governments will always play a huge part in solving big problems. They set public policy and are uniquely able to provide the resources to make sure solutions reach everyone who needs them. They also fund basic research, which is a crucial component of the innovation that improves life for everyone.

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.

Well, there's no question that the law passed in 1996 was flawed. It deregulated the wholesale market, meaning the price that the utilities had to pay energy companies for power, but not the retail market.

My first job in TV was hosting this young teen magazine show, and all these high school teenagers showed up from all over Sacramento, California, and they chose four of us to host the show, two boys and two girls. And of the two girls, I was kind of the perky smart one and the other girl was the pretty one.