Dean Kamen, inventor of the Segway and much more. Dean has invented a water purifier that produce clean drinking water anywhere in the world from nearly any bit of contaminated sludge. Its a terrific machine but he can't find any agency, anywhere in the world that will finance the production of enough of them to really help people that need the water.
And yes, Kamen is a character. But this article about him really gives some insight into how a smart guy thinks- and is always thinking. So read the article, its good!