Interesting short film about Impro from The Guardian website:
Brian Logan explores different types of improvisation on the Edinburgh fringe, and takes a Chaucerian workshop with the 'hard bardic' group The School of Night
He meets the Phill Jupitus Quartet and finds improv breaking out of its Whose Line is it Anyway? box: taking suggestions from the audience, channelling the spirits of Sylvia Plath or Chaucer - and even daring, sometimes, not to be funny.
Also featured are the brilliant School of Night and the energetic Noise Next Door.