But why Salt Lake City? “We haven’t had a convention there since 1981,” says Mr. Muscato. “A lot of Mormons who have become atheists call themselves ex-Mormon and part of our campaign is to get them to move away from ex-Mormon” and simply call themselves atheists, thus taking pride “in their non-belief.”

The keynote speaker for the four-day gathering will be Chris Kluwe, a former punter for the Minnesota Vikings, who says he was fired for advocating same-sex marriage. Mr. Kluwe, author of “Beautifully Unique Sparkleponies: On Myths, Morons, Free Speech, Football, and Assorted Absurdities,” will be joined by speakers including Denise Stapley, winner of “Survivor: Philippines” and Iowa’s “only certified sex therapist” (according to convention publicity); Mark White, bassist from the Spin Doctors; and gay-rights activist Marsha Botzer.

Workshop topics will include starting your own atheist group, how to lobby politicians, and how to debate Christians and “other religious apologists.” The contact page at the American Atheists website states: “Please note: we are not interested in debating or being preached at,” which to some ears might sound a tad hypocritical and closed-minded, qualities often used to describe the organization’s adversaries.