A nun walks into a bus and sits behind the driver and says, "I have just one regret before I die,"
The bus driver asks "What might that be?", she says "I have never had sex, but I can't have sex with a married man or that would be a sin."
The bus driver says, "I'm not married"
The nun says, "I have to die a virgin so I will have to take it in my ass".
Being the only two in the bus they went to the back and took care of business.
When they were done the bus driver says to the nun, "I have a confession to make, I am married."
The nun says "I also have a confession to make, My name is Tom and I'm going to a costume party!"