Years ago, George Burns appeared as a guest on Johnny Carson's Tonight Show. He did a five minute comedy routine, then walked over and sat on Johnny's famous sofa.
George had just turned 95, and Johnny asked him how he managed to keep going - and doing stand up comedy - even at 100.
George: "Well, back when I was 70, my doctor told me to give up liquor, tobacco, and beautiful women".
Johnny: "But George, you had a nip of brandy before the show, you're smoking a big cigar right now, and you arrived at the theater with two gorgeous blondes. What does your doctor say now?"
George: "He died 15 years ago."