A Prairie Home Companion is a film about the live radio show presenting a mixture of folk music and comedy for the heartland of America every Saturday night. Periodically I would stumble upon show on my classical radio station, but never listened more than a few minutes because the humor was not my cup of tea. I suspect that the director Robert Altman grew up with this kind of show and was willing to make a film about a fictional last show of radio program out of sense of nostalgia for a time gone by. One could have made a beautiful film about American folk music and its cultural meaning. But the ambitions of the film are too modest.  It simply wants to preserve for posterity one of these shows and what its dominant host was like. This does not amount to much despite its great cast of actors, including Meryl Streep, Kevin Kline, Tommy Lee Jones and Woody Harrelson.