I'm going to running a pick-up game of Ars Magica on Sundays. Basically if you're at Critical Effect on a Sunday and you're not doing anything else, I'll run Ars Magica. Everyone who wants to play will be contributing at least one magi, and then you can make up a companion or several grogs.

It'll be a spring covenant, so pretty much the magi you make up will be running the place... there'll be three more experienced magi-npcs, but they'll leave the business matters to the PCs.

It'll pretty much be standard 3rd Edition ArM and anyone who wants to join in will be welcome. You don't have to be there all the time, any character who isn't available will be assumed to be off experimenting in the lab or doing research...