Bill Gates hopes to solve some of the world's biggest problems using a new kind of philanthropy. In a passionate and, yes, funny 18 minutes, he asks us to consider two big questions and how we might answer them. To hear what he has to say about education, let the video download and then fast-forward about halfway. Bill describes how a technology like IRIS that uses digital video to enable classroom observation, recording, annotation and feedback is an important part of how we can make teachers great.