'The Yolk's On You' - a headline in the Daily Star on a story about an attempt by Nick Griffin, the head of the British right-wing  BNP party to hold a press conference outside the Houses of Parliament in London after being elected as a Euro MP.  The conference was abandoned after Griffin was egged (pelted with eggs) by an angry crowd .  Instead of using the word 'joke', as in "the jokes on you",  the headline-writers used 'yolk' as in "egg yolk".