Marine Corps Association

The MCA occupies a similar role with respect to the Marine Corps that the United States Naval Institute does for the United States Navy, the Association of the United States Army does for the United States Army, and the Air Force Association does for the United States Air Force. Wikipedia*

On the C-SPAN Networks:
Marine Corps Association has hosted 2 events in the C-SPAN Video Library; the first program was a 2003 Forum.