After shaking up the face of computing early in his career, Bill Gates hopes to mix things up in the bathroom. He's just pledged $42 million to reinvent the toilet.

Ever since leaving Microsoft, he's been pursuing a number of projects with his non-profit organization in an effort to save the world, and now he turns his attention to the bathroom.

Consider this: 40% of the world's population doesn't have access to flush toilets. Water hygiene and waste disposal are two of the biggest problems facing third world countries. It might sound silly, but re-imagined toilets could be just the thing to improve the quality of life for millions of people.

The foundation is getting help from "eight universities around the world" to world to develop a standalone unit without piped-in water or electricity that will turn waste into energy, clean water, or nutrients.