We like to pay homage to Earth Day as much as we can (stretching it on to the next day and beyond) and so we give the stage to the inventor of the Segway, Dean Kamen. He has come up with a device that will turn any liquid into drinkable water and despite its huge non-prettiness and using cow dung as fuel, I think we all can appreciate that people will be able to drink who couldn't before (Frankly, most of us are drinking bad water anyway).
It will also power up to 70 energy efficient lightbulbs which is to say, it generates a lot of power. This is something that would likely be situated outside the home, like an air conditioner. It may not be pretty, but it is pretty revolutionary. Pass it on, this hasn't gotten the press it deserves.