not 'exactly' song circles as you seem to mean, and playing instruments is the big deal, though, of course, there is singing too.....There is LOTS of "campground pickin"...in fact, there are many folks who never go in to see the stage shows, but just go there to play with friends they may only see once a year. You can wander around the campground almost any hour of the day or night and find music happening, and IF you look like someone who can play, you may be invited to join in.

But take care...some of these folks are very serious about their music and it is best to learn the rules gradually. If you play an instrument, and just barge into the wrong group, you'll learn quickly.

Most of the folks are quite friendly, but most of them know each other...or some smaller group...This has been going since 1970 or so,(I attended the first 10) and it is a good idea to do 'more' listening than joining, unless you know you are GOOD. If you are, you be playing with someone quickly!

If, as it sounds like, you are primarily a singer, then just enjoy...and go hear the wonderful acts on stage, and soak up the ambiance until you get an idea what works.