A man and his wife are awoken at 3 o'clock in the morning by a knock on the door. The man gets up and goes to the door where a stranger is asking for a push.

"Not a chance" says the husband -- "It's three o'clock in the morning!" He closes the door and returns to bed.

"Who was it?" asks his wife.

"Just a stranger asking for a push" he answers.

"Did you help him? she asks.

"No I didn't -- it's three in the morning"

"Well you've got a short memory" says his wife, "Can't you remember about three months ago when we broke down on holiday and those two guys helped us?. I think you should help him."

The man does as he is told and returns to the front door and calls out into the dark "Hello -- are you still there?"

"Yes", comes the answer.

"Do you still want a push?" calls out the husband.

"Yes please!" comes the reply from the dark.

"Where are you?" asks the husband

"Over here on the swing" the man replies.