One day a hippie gets a ride on a public bus and sees a hot young nun. He sits down next to her and promptly asks if she would like to have sex, to which she immediately says no and walks off the bus. The bus driver leans over and says "Hey guy I know how to get that nun to have sex with you..."
Naturally the hippie asks, and the bus driver tells him that every night at midnight the nun goes to an old graveyard to pray for god to forgive her for her past, and that he should dress up like god and tell the nun she will be forgiven if she has sex with you.
The hippie gives his thanks and runs to the nearest costume shop.
Later that evening the hippie gets ready for his big night and drives down to the graveyard and sees the nun praying, on her knees. He says "Behold, I have heard your prayers and you shall be forgiven if you have sex with me!"
The nun agrees but asks if they can have anal sex in order to keep her virginity. The hippie agrees and once they are finished the hippie jumps back and pulls off his mask and says "Surpise, its me the Hippie!"
The nun jumps up and pulls off her mask and says "Surprise, its me the bus driver!"