From Dean Kamen (the guy who invented the Segway scooter) comes the Slingshot, a water purifying machine that turns anything wet (sewage, water from a polluted well, sea water) into drinking water. Countless people die each year from lack of access to potable water. Check out Kamen’s interview on the Colbert Report.

From Adam Grosser of Foundation Capital, the “Intermittent Absorption Refrigerator.” The idea is that millions of people die from disease and malnourishment because they can’t keep food preserved. Using the heat exchange from something that is commonly available (a cooking fire) Adam’s sustainable, portable 8-lb device can chill a normal refrigerator-sized container to just above freezing for 24 hrs at a time. Watch his brief TED talk.

Hands-down these are the two inventions that have the most potential to change the quality of life for the most number of people on the planet right now. Unfortunately inventing the prototypes is only half the battle- they now have to commercialize them successfully. Good luck fellas, these devices have amazing potential if you do.