70 year old Sidney opens his eyes and sees a lovely lady in white staring at him. "Where am I?" he says.
"You're in the Sinai hospital, Mr. Green," she replies. "You had a nasty car crash four days ago and you've been unconscious ever since you were brought in. But don't worry about anything – you're in a great hospital and we've got the best doctor looking after you."
"Four days, eh?" says Sidney, "it's no wonder I'm so hungry. Can you bring me a hot salt beef sandwich on rye with mustard and a cucumber with some latkes on the side."
"I'm sorry, your doctor has instructed me not to feed you with any solids," says the nurse. "You're being fed through an intravenous. Do you see that large tube down there? If you follow it, that's your food supply."
"Well then," says Sidney, "If this really is the best hospital with the best equipment, please bring me two more tubes tomorrow. Then I would very much like to invite you and my doctor to join me for lunch."