A hard rain is falling outside the windows of a church on Capitol Hill Friday night, and a slim, sharp, funny Christian dynamo is teaching a sanctuary full of believers about a new style of communicating the Word.

Michael Kelsey Jr., 23, son of a preacher in Northeast Washington, waves a Bible study guide before his audience and asks, "You know what my favorite part of this book is?"

Let's see -- could it be John 3:16, the famous verse about God loving the world and giving his only son? Or the prayer you pray when you resolve to follow Jesus?

No.

"My favorite part of this book is on page 55," Kelsey says, and everyone leafs to that page.

It's a "Glossary of Christian Jargon."

These are catchphrases that roll easily and regularly off the tongues of some evangelical Christians. Door of our heart . . . Great commission . . . Unequally yoked . . .

The people chuckle as Kelsey drives home his point: "No one understands what we're talking about!"

Kelsey, director of young adults at his father's church, New Samaritan Baptist, is a trainer in the tech-savvy, rock-and-roll-inflected, skateboard-friendly evangelical movement that international Christian cheerleader Luis Palau has brought to the soggy Mall this weekend. Palau's DC Festival -- motto: "Great music and good news" -- is an archetype of what is known as "festival evangelism," a step beyond old-fashioned, sermon-heavy crusades.

It's all about communication -- finding new words, even new ways beyond words, to tell an old story and offer a familiar invitation.

Six years ago Palau -- 70, born in Argentina, educated in Oregon, once mentored and employed by Billy Graham -- had the insight that he might reach more people by creating elaborate events featuring plenty of fun and food along with faith. He invited popular Christian bands, edgy Christian skateboard heroes with a portable half-pipe, and admired Christian athletes -- all to perform, and to speak of their faith. He added a section for children including characters from the faith-based VeggieTales videos. In six years, Palau's organization estimates, 4.5 million people have attended its festivals in the United States and Latin America.

It is spectacle as communication, with testimonials woven in. Christian iconography is scarce. A gospel message floats on the wings of a rock or rap lyric, or in the personal story of a tattooed skateboarder, or in the moral of a tale starring a cucumber. Words you probably won't hear much are those concerning subjects like homosexuality and abortion because, Palau has said, his mission is to emphasize what is positive and unifying.

Each day climaxes with perhaps the only traditional moment of the festival, a kind of "altar call" where Palau invites people to raise their hands if they feel ready to commit their lives to Christ.

That's where Kelsey and the people he helped train come in. Nearly 3,500 "decision counselors" were trained to help "inquirers" during that crucial moment of the hand raised and, perhaps, the heart opened.

In keeping with Palau's breaking from the old, churchy protocols, Kelsey tells his audience of about 150 Friday night not to come on too heavy. "This is different from the confrontational-style, go-knock-on-doors evangelism," he says. "Part of it is showing Christianity is not just about rules. We have fun."

There's a place for words, of course. Carefully chosen words. But avoid that jargon. According to the glossary, door of the heart is the metaphorical entrance for Jesus into one's life. The great commission is the injunction for believers to spread Jesus's message. Unequally yoked is a term for when a believer is married to a nonbeliever.

Finding the right language can be daunting for the modern evangelist. How do you reach doubters without scaring them off with a bunch of Bible-thumping?

Kelsey encourages his listeners to recall Paul, in I Corinthians 2:1-5. There Paul admits he had trouble finding the right words, too. He felt weak and scared. "My message and my preaching were not with wise and persuasive words," Paul said, "but with a demonstration of the spirit's power, so that your faith might not rest on men's wisdom, but on God's power."

The festival experience is meant to be that kind of communication-by-demonstration. Palau does the preaching, and he keeps it short. The decision counselors take their cue from the inquirers. Do they need a Bible verse, a prayer, a personal testimony from the counselor?

"Don't take on the pressure of trying to convert someone," Kelsey says. Conversions will happen "only by a demonstration of the Holy Spirit . . . that we're able to communicate," he says. Every inquirer who fills out a response card will be mailed a free CD with the text of the entire Bible and an MP3 audio file of the New Testament.

Some do's for the evangelists-in-training:

Bring a Bible, of course, Kelsey says, "in a version that a nonbeliever can understand. You remember how it was with the thees and thous and all that."

Two other important words: "Breath mints."

"Never share the breath of life with the breath of death," Kelsey says.

Here's a don't: If an inquirer confesses some outrageous sin, Kelsey says, for heaven's sake, "Please don't get this shocked face."

Despite fervent prayers that God would defy the weather forecasts, Friday night's downpour gushes into Saturday, postponing the start of the choreographed communication until early evening. The skateboarding, sports and VeggieTales are rescheduled for today.

Waiting for the show to begin, decision counselors in their identifying white or orange visors (orange is for communicators in Spanish) trudge in ankle-deep puddles.

Walking near the stage, Jennifer Yonker, 21, a student at Baptist Bible College in Clarks Summit, Pa., and her brother, Jason Yonker, 27, an excavator from Hagerstown, don't mind waiting. They aren't counselors, nor are they inquirers, they're already committed Christians who have faith the hard rain will end.

She wears a black tobyMac T-shirt, he a black Kutless T-shirt. TobyMac plays "hip-hop and high energy rock," according to the festival program. Kutless is a "quintet of straight-up Christian rockers."

The presence of the music, the skateboarding, the sports is a message, Jennifer Yonker says. "Christianity is not just about church. It's everyday life. It's society." The artists and the athletes, she says, "can show God's glory in what they're doing. That's awesome testimony in and of itself. You don't have to be a preacher. You can be an everyday person."

In a few hours, Palau would begin his more overt message. Near the end, as Kelsey explained to the counselors-in-training, Palau would say, as he does at every festival, something like, "In a moment I'm going to ask you to make a decision." He would invoke Revelation 3:20, the verse where Jesus says, "Here I am! . . . If anyone hears my voice and opens the door, I will come in . . ."

Then it would be time for hands to be raised, decisions to be made -- and it would become clear if all this communication had reached anybody.

Sisters Natasha, center, and Julie Roman from Dumfries cheer the Christian rock group Kutless at Luis Palau's DC Festival.Louis Palau prays with the group on the Mall. A typical festival climaxes with a kind of "altar call" where Palau asks people to raise their hands if they're ready to commit to Christ.Jon Micah Sumrall, lead singer of Kutless, performs at the DC Festival.