Old Mr. Levy knocked at the door of the sperm bank. A nurse came to the
   door. " Well, Sir? What can we do for you?"
   " Well, I'd like to make a contribution."
   "Aren't you a bit old for that, Sir?" asked the nurse.
   " Not at all," protested Mr Levy, beating his chest. "I may be 80 years
   old but I am as fit as a fiddle"
   So the nurse let him in, gave him a covered jar and told him to go behind
   a curtained-off closet to make the deposit.
   An hour passed, then two hours. Eventually the doctor came by.
   " Well nurse, how did Mr Levy make out ?"
   " Goodness me, I've forgotten all about him." She stood outside Mr Levy's
   closet and asked, " Well Mr Levy, how are you doing?"
    " Not so well", confessed the old man. "I've tried with my left hand -
    nothing! I've tried with my right hand - nothing! I've tried with both
    hands - but I still can't get the top off the jar.