My cousin sent this one to me ages ago:
This bloke's in bed with his missus when there's a rat-a-tat-tat on the door.
He rolls over and looks at his clock, and it's half three in the morning. Sod that for a game of soldiers, he thinks, and rolls over.
Then, a louder knock follows. "Aren't you going to answer that?" says his wife so he drags himself out of bed, and goes downstairs. He opens the door and this bloke is stood outside.
"Eh mate" says the stranger, "Can you give us a push?"
"No, piss off, it's half three. I was in bed," says the man and shuts the door.
He goes back up to bed and tells his wife what happened and she says "Dave, you are a bastard. Remember that night we broke down in the pouring rain on the way to pick the kids up from the babysitter and you had to knock on that man's house to get us started again? What would have happened if he'd told us to piss off?"
So he gets out of bed again, gets dressed, and goes downstairs. He opens the door, and not being able to see the stranger anywhere he shouts: "Eh mate, do you still want a push??" and he hears a voice cry out "Yeah please mate."
So, still being unable to see the stranger he shouts: "Where are you?" and he replies: "I'm over here on the swings."