My alltime fav... I'm Catholic, so think of it as making fun of myself, similar to Mel Brooks and his Jew jokes... so this is your warning that it is crude and pokes at religion (Catholicism in particular), so no groaning at me, because I warned you. If you get offended by that kinda stuff, don't read, k?
A bus full of nuns falls off a cliff and they all die and go up to the pearly gates. It is just like each of them could imagine... the gates of pearl, St. Peter up on a white marble podium guarding the gates, and next to him a fountain of holy water....
The nuns form a long single line to be able to, one-by-one, ask St Peter to open the gates so they may enter heaven...
The first nun approaches St. Peter. He welcomes her and asks for her final confession. The nun blushes and timidly whispers to St Peter that after she took her vow of celibacy, she looked at and gazed upon a penis. St Peter stands, tells her to wash her eyes with the holy water in the fountain, her sins will be forgiven and she can enter the gates into heaven.
The next nun comes up to St Peter, and he asks for her final confession. After cowering in shame for a minute, the nun finally admits that after her vow of chastity, she once touched a penis. St Peter tells her to wash her hand, her sins are forgive, and she can enter the gates.
All of a sudden there is a commotion in the back of the line with a nun screaming and running towards the front of the line. St Peter stands, here's the nun's shouts as "St. Peter!! St. Peter!! WAIT!!!" She reaches him, he tries to calm her down, but she is panting and frantic. He finally asks her what the problem is and she belts out "Just... let me gargle with that stuff before Sister Mary-Francis sticks her butt in it!!"