The group I have been a part of for about a year meets weekly for one campaign. We meet every Saturday around 4:30, game runs from 5:30 to 10:30. Most campaigns run about 8 months to around 1.5 years. Then the group votes on the pitched games. When someone's campaign us up, they have to wait until two campaigns have been run to pitch again- this lets everyone get a chance to run when they want, and take all the time they need to prep a game ahead of time.
The group has 7 members, and it seems everyone has a different favored system. Although, D&D 3.5 (now pathfinder) is really popular. Three GMs have shared homebrew setting featuring spelljammers, Krynn, Greyhawk, and Forgotten Realms, plus WoW stuff and every other bit of fantasy genre they get their hands on. This bleeds into other games where Dresden Files includes Percy Jackson, Highlander, and Buffy material notably featured in the powerful groups.
My only real complain about this group's playstyle is the kitchen sink approach. Every game gets loads of houserules and splatbooks which is a problem when someone is trying to learn a new system, or just make a character.
With so many GMs I'm hoping to be able to get some to play more often and have a smaller group meet up on a different day (maybe Fridays since my school doesn't have grad classes then) to play more games get more burdensome with large groups or just are an ill fit (like Burning Wheel).