In Non-governmental organizations

Colleges and Universities* (list regularly changes; more regularlly updated here)

Bates College
Boise State University
Brown University
California Institute of Technology
California Polytechnic State University
California State University at Chico
California State University at Northridge
Carleton College
Claremont-McKenna College
Clark University
Community College of Baltimore County
Connecticut College
Cornell University
Duke University
Emory University Law School
George Washington University
Georgetown University
Harvard University
Hendrix College
Humboldt State University
Johns Hopkins University
Lewis and Clark College
Luther College
Macalester College
Massachusetts Institute of Technology
McMaster University
Middlebury College
Mills College
North Carolina State University
Pitzer College
Plymouth State University
Portland State University
Rice University
Reed College
Santa Fe College
Sonoma State University
Stanford University
Tufts University
University of California at Berkeley
University of California at Davis
University of California at Los Angeles
University of California at Merced
University of California at San Diego
University of California at Santa Barbara
University of Iowa
University of Minnesota
University of Oklahoma
University of San Diego Law School
University of Toledo
University of Virginia
University of Washington
University of Wisconsin
Vassar College
Western Washington University
Whitman College
William and Mary (with contingency)
Williams College 

Political Parties (partial list)

Utah Republican Party (contingent)
Canadian Conservative Party
New Zealand Liberal Party
British Labour Party
British Liberal Democratic Party

Associations (partial list)

Academy Awards  (Best Picture)
American Association of University Women
American Chemical Society
American Geophysical Union
American Medical Student Association
American Mensa
American Political Science Association
American Psychiatric Association
American Psychological Association
Canadian Wheat Board
Consortium of College and University Media Centers
Hugo and Campbell Science Fiction Awards
International Psychoanalytical Association
Internet Corporation for Assigned Names and Numbers
National Organization for Women

*These lists change regularly. Updates can be found here.