There is a documentary series 'Independent Lens' that shows on Public Broadcasting Service. One of the best was about the Young at Heart Chorus.
http://www.pbs.org/independentlens/young-at-heart/
The video isn't available from PBS now, but here are some clips on Yahoo:

http://video.yahoo.com/watch/6719901/17453164
http://video.yahoo.com/watch/6731543
http://video.yahoo.com/watch/6751836/17547055

It's a great film. Probably not released on-line because it still makes $$$ for pledge drives. PBS is sponsored in part by donations from viewers.

The last song of the movie: "I will try to fix you"
http://www.youtube.com/watch?v=gosIuO1HqEg

Edit: Fred Knittle's obituary from the Worcester Telegram
http://www.legacy.com/obituaries/telegr ... =122128586

http://www.youngatheartchorus.com/fredknittle.php