It seems to me that what we are all about in AM Exchange is grass-roots professional development. We already embrace the move away from expert-driven learning to self-authorized learning. We already know that their are expert voices among us at New Trier who are capable of differentiation in meeting the goals/needs of other teachers. And, we already sense that professional development for teachers is most powerful when it is more personal, social, and voluntary.
These are the concepts which drive the Unconference model. Read the thoughtful blog post
"Unconference: Revolutionary Professional Learning" from M.E. Steele-Pierce who describes how unconferencing works, why it matters and how to set it up so that professional development doesn't "stink".