A Corkman walked into a pub with a big front door under his arm.
'What are you doing with that door?' the barman asked.
'Well', said the Corkman, 'last night I lost the key, so in case anybody finds
it and breaks into my house I'm carrying the door around'.
'But what happens if you lose the door?' 'That's O.K.', grinned the Corkman, 'I've
left a window open'.