Starting around 1981 or 82, in Rockford, IL, I played in a game that had been running at the neighborhood comic/record/book shop. The owner had played at cons with the TSR folks from pretty early on and ran a game that had from 8 to almost 20 people playing each night. In the beginning, some people had OD&D, some had B/X, and some had 1e and I'm not sure if anyone knew or cared who had what. As it went along it did turn more to using AD&D. I don't remember anymore when she stopped running it in the mid-80s.