Via The Times:
Kirk Douglas had a son, the little-remembered Eric Douglas, who was an actor and stand-up comedian. He once came over to the UK to do some gigs and inadvertently created one of British comedy's finest legends. Eric wasn't having a great gig at a London club; he was going down the pan. His opening line, I seem to remember, focused on the fact that he lacked the cleft in his chin possessed by both his father and brother. The audience was not in the least interested. Their indifference eventually overwhelmed him and he finally shouted: "Do you know who I am? I'm Kirk Douglas's son!" The room looked on in silence, then someone in the audience stood up and said: "No, I'm Kirk Douglas's son." He was swiftly followed by several more. Within seconds, the entire audience was on their feet, all claiming to be Kirk Douglas's son, in a pitch-perfect parody of the scene in Spartacus. That, by anyone's standards, is a tough gig.
Read on: A nice discussion of the dark side of heckling going on at The Guardian.