The North American Society of Tinkerers is an organization for inventors on Fraggle Rock, promoting both social events and academic reports on new developments in the field. Doc is a member, despite claiming that the society has no imagination. The group was first mentioned in "Wembley and the Gorgs," in which they selected Doc as Man of the Year. Their award, interestingly, bears the name "International Society of Tinkerers."
They also publish The Tinkerers' Quarterly.