The tag line of a new church in the Bronx whose congregants are in their 20s, sounds like a Pepsi ad from a few years ago.

Though the church had its first service on a Saturday night in November, its pastor is hopeful that his congregation, the Experience, will indeed grow to become “the church of a new generation,” as a banner inside the church reads.

“We’re targeting people that would normally have a negative concept of church, to tell them church is fun,” the pastor, Reverend Loammi Diaz, 28, said before a recent Saturday night service. “We emphasize people, relationships. It doesn’t have to be a starchy experience.”

Then he added: “Church is cool.”

A few minutes later, the lights dimmed, the band ripped into a rocking hymn, and an MTV-like video appeared on the projection screen. Church was in session.

The Experience is part of a growing handful of churches in the city that cater to New Yorkers in their 20s and 30s, for whom brunch has replaced church as their Sunday ritual. Young pastors in the city are beginning to address what a Christian research organization, the Barna Group, has called the “faith quakes reverberating through our nation’s young adults,” which is the plummeting rate of church attendance among people in their late 20s.

Nationwide, three in 10 people in their 20s attend church in a typical week, compared to nearly half of adults older than 40, according to the Barna Group’s research.

This is not simply because of the distractions of college or the pressures of a new job, with which many young New Yorkers are familiar. Young people in the throes of finding their place in the world crave community and spirituality, but most do not find sustenance in formal, traditional church settings, the report’s author, David Kinnaman, said.

“One of the reasons why niche-oriented congregations are springing up is that the one-size-fits-all church is finding a difficult time being relevant to a generation used to customized marketing,” he said.

Using the tools of Madison Avenue, where image is everything, these churches combine video, live music, PowerPoint slides, and skits in an effort to make church relevant to their young congregants.

To be sure, these are not the churches of yesteryear, whose names, like the Church of the Holy Nativity or the Christ Temple Baptist Church, were explicitly religious. Instead, they are decentralized from the particulars of denomination and conjure images of personal process with such names as the Experience, the Journey, and Mosaic.

After Ashlee Simpson was caught lip-synching on “Saturday Night Live,” the pastor of Mosaic Manhattan Church in TriBeCa, Gregg Farah, staged his own impromptu version of the Simpson debacle. Standing several feet from his microphone, he lip-synched his Sunday sermon, to illustrate a point: Pastors shouldn’t use backup tracks. The entertainment value has been one hook he uses to reach out to new audiences.

“People say, ‘I like coming because I never know what to expect,'” Rev. Farah, 37, said. “Our services have a less linear, more organic flow.”

Pop songs like Fleetwood Mac’s “Little Lies” help him illustrate other lessons.

“We want people to hear that song outside of church and let the song be a teaching tool in a way it wasn’t intended,” he said.

Another church, the Journey, does not advertise its Southern Baptist roots, calling itself a “casual, contemporary Christian Church designed specifically for New York City.” It launched its first service on Easter 2002.

“It’s a church that isn’t afraid to talk openly about relationships … use technology to assist you in your spiritual journey … use the arts to worship and celebrate God … talk authentically about work, life and the next steps in our relationship with God,” the Journey’s Web site says.

A recent service in the auditorium of the Levy School at the Lower East Side felt a bit like a rock concert and a bit like a college lecture. At the door, volunteers handed out pens along with the program. A band played a rocking medley of hymns. At the back of the auditorium, church members dressed in the black clothes of stagehands recorded the show, mixed audio, and worked the stage lights. A guest pastor delivered the sermon outlined by a PowerPoint presentation on a large screen.

“What on earth am I here for?” the screen read.

Chris Brady pondered that question two years ago. At the time, Mr. Brady, now 40, was a lonely and struggling actor who had not attended church since he was 14. Unhappy at his day job as a computer consultant, he stayed at home, smoked pot, and played video games. “The choices I’ve made aren’t working for me,” he recalls saying to himself.

He stumbled upon the church when a volunteer handed him a flier advertising its film series exploring the moral questions found in summer blockbusters. He was soon hooked into the community. “Now an audition doesn’t make or break me,” he said.

The church has also helped Casey Kern answer that question. She arrived in New York in January 2001 from Port Saint Lucie, Fla., hoping, like so many others, to make it in the city as an actor. “I knew it wasn’t going to be easy, but I thought I could do it on my own, and for two years I did,” Ms. Kern, 30, said. “Now that I came to this church I know I never want to do it on my own again.” She combines her “material and spiritual gifts,” volunteering as a stage manager for the church, which has outgrown its space and will soon move to the Manhattan Center Studios.

Dustin Bagby, 24, a pastor who works at Mosaic Manhattan, plans to open a similar church late this year at the Lower East Side. While he will use the tools of his trade familiar to Mosaic, he echoes the sentiments of other pastors who say rock music and videos cannot replace authentic congregations who also contribute to the community at large.

“You need to make yourself a loving community that’s going to be there for a while,” he said. “No amount of coolness is going to do that.”