Four groups:
#1) I DM for a group of 8 players, once a month, Friday nights. 3.5, Forgotten Realms - Silver Marches. Group has been together for about 13 years, in various incarnations; I've been with it for 10, and DMing it for 7.
#2) I DM for a group of 3 players, once a month, Sunday nights. 3.5, Forgotten Realms - Cormyr. Group has been together for 4 years, I've been in it from the start, and have been the DM for the past 3 years.
#3) My original group, from my home town, is now spread out over 2 states. Most, if not all, 7 of us get together to play 5-7 times a year (2 of those get-togethers are multi-day game-a-thons). We play 3.5, Star Wars, Spycraft, Living Death, and more. Group has been together for 25 years, with a rather fluid membership over those years; I've been with it for 23 years, and have been the primary DM for the past 15 years or so.
#4) I play various RPGA campaigns online with a loose-knit group of about two dozen players. We play something (Living Force is our favorite) every week or two, on weekday evenings.