Alternate Tuesdays, I'm in a group playing a Dragonlance game.
Thursdays I'm in a group, alternating playing the Buffy RPG and a no-magic alternate D&D game.
Fridays I alternate between running an Eberron game, and running a local drop-in Living Greyhawk game.
Alternate Saturdays I run a Pirate LARP (who wouldn't want to dress up like pirates, wave plastic swords around and say Arr?)
Alternate Sundays I'm peripherally involved with a playtest of a homegrown sci-fi system.
That's 6 groups, with Fridays alternating. There's a fair emount of overlap between them, but far from total. I also play and run Living Greyhawk (for which I was just made a Triad) pretty often on other days than Fridays, but that's not a regular thing.
--Seule