On Halloween, a nun flags down a cab and gets inside. The cabbie gets fidgety, and finally, in a sudden honest rush, tells her:

"You know, it's always been a fantasy of mine to have a nun kiss me."

The nun looks at him. "Brother, I can fulfil your fantasy on two conditions. First, you have to be single, and second you have to be Catholic."

The cabbie gets excited. "Yes, yes, I'm single and I'm Catholic!"

He pulls over and the nun fulfils his fantasy.

But afterwards he is sorrowful. "Sister, I have sinned. I'm Jewish and I'm married."

"That's okay, Brother," says the nun, "I'm on my way to a Halloween party and this costume is just an old habit."