The wealthy couple were celebrating their 35th wedding anniversary. Their three grown sons joined them for dinner. The old man was rather irritated when he discovered that none of the boys had bothered to bring a gift, and after the meal, he drew them aside.

'You're all grown men,' he said, 'and old enough to hear this. Your mother and I have never been legally married.'

'What?' gasped one of the sons. 'Do you mean to say we're all bastards?'

'Yes,' snapped the old man, closing the trap, 'and cheap ones, too!'