Not Spartacus

A cruel but funny story about Eric Douglas - Kirk's son and Michael's brother.

Eric Douglas had tried working as a stand-up comic. During one session which wasn't going well, he called out to the audience, 'Don't you know who I am? I'm Kirk Douglas's son!' After a moment someone at the back stood up and said, 'No, I'm Kirk Douglas's son!' Someone else then followed suit with 'No, I'm Kirk Douglas's son!' and soon the whole audience was chiming in: 'I am Kirk Douglas's son!'

There are versions here, here and here. See this if you need the explanatory reference. (Hat tip: Lionel Keet.)