Reminds me of a joke.

One afternoon, as Einstein and his driver were headed to yet another lecture in yet another college lecture hall, Einstein had an idea. Speaking to his driver , Einstein said, "I really don't feel up to giving my lecture tonight. Why don't you deliver it? " " Me? " gasped the shocked driver.

"Yes," replied Einstein. "You have heard me give it scores of time. I'm sure you must have it memorised by now. " " What if there are questions? " asked the driver. " There are never any questions, are there? There is nothing to worry about," returned Einstein.

And so the ruse was planned. They would change cloths and switch roles. On arriving at campus, the driver was accorded the welcome appropriate for a famous Physicist, and Einstein tagged along behind, as was suitable for a man of his status. The lecture went beautifully, as Einstein knew it would.

At the end of the lecture the driver dutifully asked for questions. To the horror of both the driver and Einstein, a man stood up in the audience and asked a detailed question about an obscure point of the theory of relativity. The driver looked at Einstein with fear in his eyes but then regained his composure, began to smile and looking directly at the gentleman replied, " That question is a very simple one to answer." Then gesturing to Einstein, who was at the back of the hall dressed his driver's garb, the driver continued, " In fact that is such an easy question that I would like to invite my driver to the stage to answer it."