Nothing Opens On A Sunday

A good citizen of Castlereagh was on his way home from church when he came across a man lying in the middle of the road, covered in blood.
'Good heavens, man, what happened to you?' he asked.
The engine of my plane blew up and I had to bale out,' said the man. 'But my parachute didn't open.'
'Ah yes,' said the Castlereagh man. 'You'll find that nothing opens around here on Sunday.'