There's little talk about organized religion, positive or negative.
Likewise, down in Louisiana, said his atheist services will not be anti-religion.
"What we are looking at doing is different," DeWitt said. "If you are a religionist and you come and sit in our pew, the only way you can leave offended is because of what you don't hear and what you don't see. We won't be there to make a stance against religion or against God."
Coming out of the closet
In the last few years, the number of "nones" -- those who don't associate with any organized religion -- has grown at a rate faster than any other group. Nones now represent one in five Americans, according to a 2012 Pew Research Center poll.
Although the number of atheists has grown, too, there are still a large number of "nones" that choose not to associate with the label "atheist."
Some at Harvard's Humanist congregation fall into this category.
"I don't particularly have a religion," said Anil Nyer, a neurologist who brought his daughter to Humanist Sunday school. But Nyer also said he didn't want to label himself as an atheist.
One reason to shy away from the atheist label: Many Americans hold a negative impression of nonbelievers.
According to a recent Public Religion Research Institute poll, nearly 40 percent of Americans believe that atheists are changing American culture for the worse.
"Whenever we put atheists on a list like this and we compare them to other groups, atheists tend to come in towards the bottom of that list," said Robert P. Jones is the CEO of Public Religion Research Institute.
"Americans tend to hold a lot of reservations about atheists."
Epstein hopes his congregation can change that.
By formalizing meetings and building a strong community, the Harvard group hopes it can be a model for other atheist congregations forming around the country.
A group meets during an atheist gathering in Boston.
More atheists may come of the closet if they know a congregation will be there to support them, Epstein said,
"Being an atheist is something we want people to come out and be," said the Humanist chaplain. "There are so many people, probably millions, who are humanists or atheists or nonreligious in private and nobody knows."
Epstein said he gets e-mails daily from people founding atheist meet-up groups.
"Tulsa, Oklahoma; North Carolina; London; Vancouver, Canada; Houston, Texas," Epstein said, listing the sources of the most recent e-mails.
"One part of what we are saying is come on out and let your neighbors know" about your disbelief, he said. "It is not going to make you worse of a person, it is going to make you a better person to be more open about who you are."
Rituals for the irreligious
For the last few years, the Humanist Community at Harvard has operated out of a small three-floor walk-up off the bustling streets of Harvard Square. The walls are littered with posters about atheism -- tributes to famed atheists Eddie Izzard, Seth MacFarlane and Stephen Fry.
Because of the scattered furniture and the Harvard dorm feel, Epstein jokingly describes the space as "college broke chic." That's being generous -- but it's also about to change.
Starting in the fall, the Humanist Community at Harvard will begin meeting in a nearly 3,000-square-foot community center with an event space for nearly 100 people.
Although the plan is to use the space at the group's headquarters, it will also serve as a broader community center for the group that Epstein and others are trying to build in the Boston area.