One day a doctor, a farmer and the president of an HMO arrive at the Pearly Gates. St. Peter hesitates, because heaven is getting kind of full. Finally he tells the doctor, "You may come in, for you have taken care of the sick in their time of need." Then he turns to the farmer and says, "And you, too, may enter, for you have grown food to nourish your fellow man." 

Then St. Peter turns to the HMO executive. "Well, I guess you can come in too - but only for three days."