My favourite is from Einstein’s chauffeur who, having heard the great man give the same speech many times had switched places with his passenger and delivered Einstein’s lecture in his place. A tricky moment arose at the end when a member of of the audience asked him a question about the fine detail of relativity – which is when the chauffer displayed his true intelligence.
“That’s such an easy question,” the chauffeur responded from the lecturn. “In fact, it’s so simple, I’m going to have my chauffeur answer for you.” And turned to where Einstein was lurking at the back, disguised beneath the chauffeur’s cap.