This workshop I went to last weekend centers on one instrument: the hardanger fiddle or hardingfele. It's the Norwegian national instrument, it has extra strings, it's totally cool-looking. No, I don't play fiddle, but I love the dances that are done to the fiddle and the songs I was learning are mostly fiddle tunes. Every night at the beginning of the dancing, the fiddle students did something called "lagspel" or "group play" in which they play together and we dance around the outside. See those three couples at the top left? They're doing a waltz or a reinlender or something.
The hardingfele is really a solo instrument, and when you have a bunch of them playing in one room, it's a bit cacophonous. It is not a sound of which the hardanger purist would approve, and it's definitely not as good for dancing as a solo instrument. But I still love it. The tunes are cheerful and the students are having a good time, and it's one heck of a joyful noise.