What is a Social Entrepreneur? We have two answers for you on this week's show. First we'll speak with Dan Biederman. He's the co-founder of the Bryant Park Corporation in New York, a private organization that transformed Bryant Park from a dangerous and depressing eyesore to one of the best loved and most intensely used urban parks in the world.

We'll also speak with Pamela Hartigan. She's the founding director of Volans, a venture company dedicated to social innovation. She's written a book about social entrepreneurs called "The Power of Unreasonable People." We'll speak with Pamela about the book and what Unreasonable People do to enrich and improve the world around them.