These folk are trying to make a difference. Dan Austin is founder of 88Bikes.org, which brings bikes to impoverished kids around the world. Matthew Frey works for PATH (path.org), an organization that has developed Ultra Rice, a fortified staple with micronutrients. Christiane Leitinger runs Pennies for Peace (penniesforpeace.org), a group founded by Greg Mortenson that helps students broaden their cultural horizons. Hank Louis is an architect who runs Design Bluff (designbuildbluff.org), which builds cheap, sustainable housing for Native Americans. What works, what doesn’t and why?