PBS has made a documentary whose subject matter strikes dead center at my sensibilities. During the heyday of TV talk shows, Dick Cavett, the Nebraskan Yalie  became friends with Groucho Marx,  a man  who is nearly impossible to capture in words. Groucho's whole act was about pauses and raised eyebrows and a tone of voice glazed with contempt. That they were friends makes my heart sing a little. Each of them embodies something great about 20th Century entertainment - something that is lost. Marx was from the world of Vaudeville when there could never be a dull moment and gags were delivered like confetti. He was as natural a performer as ever existed and had a comedic inflection that was like spun gold. He was a natural in some of the best comedy films ever made and then adapted to television, able to play off any line. The world was his straight man. Cavett, the buttoned up intellect with the gleam in his eye, never stopped being a fan, but also became a kindred spirit. Their careers spanned different generations but both respected their audiences' intelligence and knew when less was more. Seeing them perform a duet together you can tell they're having the time of their lives.