(ABC News) -- Sanderson Jones, who grew up in a religious British family, described the death of his mother when he was only 10 and his subsequent loss of faith as a "cataclysmic catastrophic event."
He loved the rituals of the Christian church in which he was raised, but could not get his head around why God would allow cancer to take his mother -- a Sunday school teacher with five children -- at the age of 42.
"Losing faith meant that she had to die twice," said Sanderson, now 32 and living in London. "Once when she went to heaven and then when I realized heaven didn't exist. It meant I had to work out a way to understand life and for me, it was realizing that instead of being angry that she was taken away so soon, I became overjoyed that I had ever been loved by her at all."
So today, Sanderson, an atheist and stand-up comedian known for selling his show tickets by hand, leads the Sunday Assembly, a community of godless congregants that began in London and is now being exported to the United States.
From Oct. 20, when its crowd-sourcing campaign begins, to Dec. 15, the assembly will launch 30 new groups in Britain, Canada, Australia and the United States.
Recently, at the first-ever service in the English seaside town of Brighton, 240 atheists turned up for sermon-like speakers, readings, singing -- and all the things you would expect in a religious setting.
"We talk about developing an attitude of gratitude," Sanderson told ABCNews.com. "It's catchy, isn't it?"
"It's like TED for the soul," he said referring to the nonprofit devoted to new ideas.
Sanderson said he was tired of the dour meetings held by the Humanists and the Unitarians.
"Why on earth aren't people clapping and dancing around and jumping up and down at those gatherings?" he asked.
Sanderson concedes that "church" in the U.S. has "certain bad associations" but, he says, the idea of organized atheism is catching on.
More than 400 atheists have recently signed up online to attend a Sunday Assembly in Los Angeles scheduled for Nov. 10.
In New York City in June, more than 130 met in an Irish pub and the numbers are growing. Sanderson admits that a bar is not the ideal meeting place, but a start.
Groups in Chicago, Washington, D.C., San Diego, San Francisco, Atlanta, Nashville, and Phoenix, among others, are also forming.
"We wanted to do something like a church for people who don't believe in God," said Sanderson. "Life is such a wonderful thing to have been given -- and frankly, it's as transcendent as any one god. We come from nothing and go to nothing and in between we have these short glazing moments of awareness and consciousness to love and sing and mess up and try again. We should celebrate it."
Sanderson leads many of the services with his friend and co-leader Pippa Evans, who is also a stand-up comedian.
"We call ourselves hosts," he said. "We think of it like a host at a party, serving them and making them feel welcome."
The assembly is also hoping to offer church-like rituals for life's big events -- marriage, birth and death. "It's a shame conventional funerals aren't celebratory enough," said Sanderson.
"People who go to church are healthier, wealthier, live longer and are happier," he said. "One of the best things about church is that it is a safe place for everyone and appeals to people with families as well."
The phenomenon could tap into a growing group of nonbelievers in the United States.
According to Pew Research Center's Religion & Public Life Project, there has been an increase in the number of American adults who say they seldom attend religious services and those who do not identify with any religion at all.
About one-fifth of the public overall -- and a third of adults under age 30 -- is religiously unaffiliated as of 2012, according to Pew Research.
Fully a third of U.S. adults say they do not consider themselves a "religious person." And two-thirds of Americans -- affiliated and unaffiliated alike -- say religion is losing its influence in Americans' lives.
About 5 percent of all Americans say they do not believe in God or a universal spirit, but only about one quarter of these nonbelievers actually call themselves atheists.
One, Roy Speckhardt, who is executive director of the American Humanist Association, likes the idea of the Sunday Assembly, citing its "technology, entertainment and humor."
"It's not like what we have done before with weekly lectures and a gathering lunch afterwards," he told ABCNews.com.
"Our meetings are mostly academic and somewhat social. That's nice, but it's not quite the community atmosphere that you get in a modern church today. [The Sunday Assembly] has taken pages from of the book from the new churches in the Northwest top get their message across."
"The megachurch environment is the highest level of entertainment and not just a weekly moment with your pastor -- it's much more structured than that. It's working in a big way in the UK and could definitely work here, too," he said of the Sunday Assembly.
The American Humanists do "good without a god," he said, and are an advocacy organization in science, politics and legal work.
Speckhardt agrees that the Sunday Assembly could tap into the large group of nonbelievers in the United States. But, he warns, "Atheists are a tough group to get together for a lot of reasons. … [They] have been burned by the religious environment and don't want to do church-like things."
But many nonbelievers "could come out of the woodwork later if a certain critical mass is reached," he said.
Speckhardt points to other Pew studies that show one third of Americans "connected to their faith" do not believe in God.
"They are ripe for this," he said. "If 1.5 Catholics are not sure there is a god, that's over 500,000 people. There is a mind-boggling potential."
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