it is a large community event, with a mailing list and a 30+ year history. i inherited the management of it from its founder about 10 years ago; he is now 90 years old! there are usually around ~40-50 people present at any given time, though the late-night is usualy thinner. there's a summer iteration as well, from sunrise to sunset outdoors (the winter one is indoors except for the midnight ritual and a sweat ceremony for those who wish).