Dungeons and Dragons
Every so often, at the SyndCon events, someone would host a D&D game. The first recollection of that was at the 2004 SyndCon in Las Vegas. Since then its happened intermittently and often resulted in all night and multi-day games across the annual SyndCon event. At the 2019 event, there was massive interest. And with the prevalence of online tools to facilate dice rolls, seeing the map space etc.. it was decided to try to host games on a weekly basis, and have multiple Syndicate parties adventuring in the same 'world' that may come across each other or may not. So we put in place the schedule. Members signed up for times they could make (which determined the party they were in and what adventure they were on) and games began. There was some initial concern that it would die out fast, since asking folks to show up every week at the same time seemed destined to fail but it didn't. It remained highly popular and there is even a waiting list of folks wanting to join in.