Jacqueline Novogratz, One of my favorite speaker!
As we work on H1N1 and larger world concerns, her experiences shows how we're not here to save the world but to solve problems, hoping for the better. Many lessons that we learn in Conceptual class are relevant to the methods that she faced in the field - in a broader sense.
You can read her talk - transcript is available on the right side.
I hope this is inspiring, as it was for me. :)