I read Ann Barnhardt's post on the Society for Creative Anachronism and remembered the stories a friend used to tell about her Renaissance Fair days. She'd stay for a weekend or more and only stopped because she couldn't afford to do it anymore and she got married to a man who didn't care for those people. What goes on at camp at night when the tourists go home is distasteful and the friends that she made were horribly immoral sorts who played musical beds within the group.
If you are invited to stay overnight at a gathering you may not be asked to participate in the sexual goings on -- my friend was not, largely because of her age and because the older person who first invited her warned everyone off from messing with her --- but you will see and hear raunchy, filthy stuff that is better left alone for the safety of your soul.