And here are the nine runners-up:

2) An old man is dying in his hovel on the steppes.
There is a menacing banging on the door.
‘Whose there?’ the old man asks.
‘Death ‘comes the reply.
‘Thank God for that,’ he says, ‘I thought it was the KGB.’
http://timesonline.typepad.com/comment/2008/06/top-ten-communi.html