Here are a few (slightly edited) gems from the Penguin Dictionary of Modern Humorous Quotations:

1) Someone asked Bertrand Russell what he would say when he died and was brought face to face with his maker. He replied: “God, I shall say, why did you make the evidence for your existence so insufficient?”

2) “An atheist is a man who has no invisible means of support.” (John Buchan)

3) “Atheism [is] a sort of crutch for those who can’t stand the reality of God.” (Tom Stoppard)

4) “Go to church this Sunday – avoid the Christmas rush.” (Graffito)

5) “In real life, Keaton believes in God. But she also believes that the radio works because there are tiny people inside it.” (Woody Allen)

6) “I’m a man of no convictions – at least I think I am.” (Christopher Hampton)

7) “The trouble with born-again Christians is that they are an even bigger pain the second time around.” (Herb Caen)

8) “If I had been the Virgin Mary, I would have said ‘No’.” (Stevie Smith)

9) “Every day people are straying away from the church and going back to God.” (Lenny Bruce)

10) “I do benefits for all religions – I’d hate to blow the hereafter on a technicality.” (Bob Hope)