Today's the start of the trip of a lifetime for single mom Sue Sandford of Dallas, Texas, and her four children. Sue's calling the trip "World School." That's because it's not a vacation: It's an education. Sue feels, as many of us traveling moms and dads do, that there's no better education--or incubator of global citizenship--than travel. Sue and her kids will be spending much of their time in each country visiting schools, befriending the local children, and getting their hands dirty helpi...