The Association of Computer Experimenters was a Canadian 1802 users group, founded in 1977 through the efforts of Tom Crawford and Eugene Tekatch. The group attracted hundreds of members from around the world with its excellent newsletter, Ipso Facto, the entire archive of which is available here in the form of searchable PDFs.
Also available here: DeFacto, an edited compilation of the first 18 issues of Ipso Facto — over 600 pages of COSMAC goodness (about 382 MB).
From the foreward of DeFacto by Bernie Murphy: “DeFacto and Ipso Facto are published by the Association of Computer Experimenters (ACE), a non-profit, educational organization. Information contained in DeFacto and Ipso Facto is believed to be accurate and reliable. However, no responsibility is assumed by the Association of Computer Experimenters, the executive, the editorial or publishing officers for its use, nor for infringements of patents or other rights of third parties which may result from its use. The contents of DeFacto and Ipso Facto may be used for any non-commercial purpose provided credit is given to the author and to the source.”