This snippet from a montage (hence the background music) of live “Ten O’clock News” on-set interviews is, by far, the funniest and quirkiest to make air during the 15-year tenure of the Boston broadcast. Even Will Ferrell couldn’t make this one up. From the very first words out of the mouth of Professor Irwin Corey, the normally stern-faced newsman, Christopher Lydon, simply lost all composure. Christopher couldn’t stop laughing. Odds are you’ll be laughing too.