Ethics professor Peter Singer’s class at Princeton, Giving 101, is wildly popular even though it digs into really touchy territory. Anybody would save a drowning kid right in front of them. But what about the kids around the world who die every day from starvation? The class teaches students about charitable giving and how to make the world a better place. It’s a lesson we could probably all stand to learn. (For us non-Princeton types, check out Singer’s The Life You Can Save site. It even has a calculator for how much you should give based on your income.)