Musk may be the world's busiest man. He is co-founder and CEO of electric car maker Tesla, founder and CEO of rocket company SpaceX, and the chairman of solar power provider SolarCity. And still, he's tacking on projects. This year, Musk unveiled a much-hyped proposal for urban transit that he called the Hyperloop, which he said would be able to transport passengers from Los Angeles to San Francisco in just 30 minutes, at 350 miles per hour. He also showed off a prototype for a computer program that you can control by simply moving your hands (a la the "Iron Man" movies) . Far-fetched? Sure. But so was the idea that an electric car company could be profitable, and Musk's Tesla managed that this year. Still too soon to say about his plans to get that car to drive itself, though.