Overturn

Write any jokes you know here.
To start you off:

A penguin walks into a bar, and says
"Do you have any fish?" The barmen says
"This a bar, we don't serve fish", and the penguin sadly waddles out.

The next day, the penguin waddles back in and asks
"Do you have any fish?", and the barmen says
"This is a bar, we don't have any fish, and if you ask me again I'll nail your flippers to the door" so, sadly, the penguin walks out of the bar.

The next day, the penguin comes in and asks "Do you have any nails?"
"No."
"Do you have any fish?"

Slightly long-winded, I know.

__________________
'If you steal from one author it's plagiarism; if you steal from many it's research.'
Wilson Mizner