Heroquest
Heroquest is a Live-action role-playing (LRP) group. There are lots of them, many are very good, and this is the one I like best. Excellent company, fantastic adventure, desperate fights against terrible foes, then feasting and drinking each night.
There are plenty of good descriptions of what LRP is about. The Heroquest website is as good as any, but apart from the costume and adventure, it's also about cameraderie, life in the outdoors, having a good time with your friends and laughing your head off.
Like many LRP groups, Heroquest is packed full of creative people: artists, costume makers, armourers, make-up artists, jewellers, story-tellers and film makers. Some do it for a living, others for pleasure.