1. A method of distributing a motion picture to a plurality of theaters where the motion picture will be presented to audiences, and wherein each theater has a cooperative-download client, the method comprising, in order: distributing chunks of the motion picture to just a subset of the theaters, wherein each theater to which a chunk is distributed becomes a seed theater for that chunk; and after distributing the chunks to the subset of theaters, directing the plurality of theaters to share the chunks among each other via a communication network, so that all of the theaters ultimately receive all of the chunks of the motion picture, wherein directing the plurality of theaters to share the chunks among each other so that all of the theaters receive all of the chunks of the motion picture comprises a media controller sending to each theater a control signal directing the cooperative-download client at the theater to turn on cooperative-download broadcasting, so that the cooperative-download clients at the other theaters can then learn what pieces of the chunks are available to obtain from other theaters' cooperative-download clients.