NB: Here are organizations and ideas which I have found personally rewarding and, in some cases, with which I am personally involved (*). I heartily recommend and endorse them. However, these organizations have not solicited my endorsement, nor should the same be construed as anything but my personal approval.
Professional
New York Organizational Learning Interest Group*
Ideologi Universal Idea Exchange*
Society for Organizational Learning*
Working Today - Freelancer's Union
Academic
Columbia University Collective Dynamics Group
Teachers College EdLab - The Future of Education
Recreational
Columbia University Hiking Club
Inspirational
The Long Now - Millennium Clock
Cooper Hewitt National Design Museum