Here's a few minutes from a 1962 Canadian TV show in which Bert Lahr, Buster Keaton and Eddie Foy discuss what's funny. They were in Canada in '62 making a dreadful movie called Ten Girls Ago, providing comic support for the leading man, who was Dion of the rock 'n' roll group, Dion and the Belmonts. It was Lahr's last completed film (he died during the filming of the subsequent The Night They Raided Minsky's) and the producers ran out of money and stiffed the actors for their final week's salary. Yet here they are discussing important things like why it's funny to hit someone with a pie…