One of the best "festivals" I ever went to was an informal dance weekend on the medium-sized island, Inis Meáin (the two stone forts there, Dún Chonchúir and Dún Fearbhaí, are magnificent). We all brought instruments and it turned into a mini-fest - it was fantastic to hear the locals sing some of their songs: one of them did their version of The Lament of the Three Marys which I'd never heard before.

The thing about the Irish is, they're used to creating their own entertainment with whom- and whatever means are at hand. That's why the traditional culture is so strong and there are so many impromptu events that aren't publicised because they haven't been planned in advance.