Matt Berg is the ICT Coordinator on the Millenium Villages Project at Columbia University. As part of that project he's been building technical systems in developing countries. He's involved with RapidSMS and projects include work in Kenya, South Senegal, Malawi and Rwanda that help children with malaria and malnutrition. And it's all using open source software and Django.
Not only does Matt do interesting work that is helping people right now, but he passionately believes that he can use Django and other technologies to make a difference. His passion and dedication is infectious, as you'll find out.