I asked Chris, of the stoical Stoa, about A Mighty Wind which he saw a couple of weeks ago (he has the link to the site). And he said:
A Mighty Wind is a film by the people who made This is Spinal Tap all those years ago. I think it's no longer on general release, but it'll keep coming back in repertory cinemas for, I hope, a long time to come. The film is one of those mock documentaries, the premise being that following the death of Irving Steinbloom, the bands that he worked with in the early 1960s re-form in order to play a final memorial concert. Most of the film is taken up with telling the story of how three different folk acts - The Folksmen, Mitch and Mickey and the New Main Street Singers - get back together again and relearn their old songs. It's very funny indeed, a gentle, affectionate satire of the very early sixties moment in American folk music, just before Bob Dylan came along and changed if not everything then quite a lot. And the dozen or so songs that were written for the film are very cleverly done - in some ways like the songs written for Robert Altman's Nashville: songs that aren't quite out and out parodies of the genre. It's great fun. And the film's engaging and (I thought) idiosyncratic linking of American folk music and Jewishness made me think it'd be a film you'd enjoy.Certainly sounds like it.