Historically, it might be Fox Hollow (1965-1979). But these days, I'd say Old Songs. Though I'd second Sandy Paton's nomination of the Getaway if it weren't such a conflict of interest for me. (I'm this year's chair).

Then again, the little group we had on our front porch Sunday evening wasn't half bad...

And SandyBob, another good on-line resource listing folk festivals can be found compliments of Dirty Linen.

--Charlie Baum.