The Freedom From Religion Foundation started informing Chicagoans this week with ads on city buses that it’s OK to sleep in on Sundays. Yes, City of the Big Shoulders, religion is not your cross to bear (and yes, Illinois native son Carl Sandburg was a freethinker).

FFRF’s large “king” ad that says “Sleep In On Sundays” in Gothic lettering will be on the exteriors of 75 Chicago buses.

“Obviously, there are many reasons to reject religion, most of them intellectual,” said Dan Barker, FFRF co-president. “But face it — one of the immediate benefits of quitting church, besides getting a 10 percent raise because you can stop tithing, is getting to sleep in on Sundays! What the world really needs is a good night’s sleep.”

FFRF started using the slogan in 2009 after it was deemed too controversial to be placed on buses as part of an ad campaign by the Atheist Foundation of Australia. “We like the idea of running a message that has been censored elsewhere,” said Annie Laurie Gaylor, FFRF co-president.

Riders will also see 200 interior bus signs with quotations from five famous freethinkers or skeptics of history, plus a quote from a contemporary: evolutionary biologist Richard Dawkins, author of the blockbuster bestseller, “The God Delusion.” Dawkins’ smiling face is juxtaposed by one of the famous lines from that work: “The God of the Old Testament is arguably the most unpleasant character in all fiction.”

The quotation selected for Clarence Darrow, the agnostic “attorney for the damned” who famously represented John Scopes in the 1925 “monkey trial” in Dayton, Tenn., is: “I don’t believe in God, because I don’t believe in Mother Goose.”

A poem by Emily Dickinson is featured:
“Faith” is a fine invention
When gentlemen can see —
But microscopes are prudent
In an emergency!

Dickinson, Gaylor pointed out, wrote some conventional poetry about religion, but as she got older, increasingly reflected a skeptical viewpoint. The poet refused pressure to join her family church, and stopped attending church altogether by her late 20s.

Actress Butterfly McQueen, famous for her typecast role as “Prissy” in the movie “Gone with the Wind,” was a nearly lifelong atheist, and a lifetime member of FFRF. In a 1989 interview with the Atlanta Journal-Constitution, McQueen said: “As my ancestors are free from slavery, I am free from the slavery of religion.”

A cryptic quote from “Puddinhead Wilson” by atheist Mark Twain is also featured: “Faith is believing what you know ain’t so.”

Actress Katharine Hepburn’s featured quote: “I’m an atheist, and that’s it. I believe that there’s nothing we can know except that we should be kind to each other and do what we can for other people.”

Getting back to Carl Sandburg’s “Chicago”:

“Come and show me another city with lifted head singing
so proud to be alive and coarse and strong and cunning.”

That’s Chicago, all right — strong, and smart and confident enough to sleep in on Sunday.