Summer Madness has all the guitars, dancing and late nights of other rock festivals. But the 5,000 visitors can forget about mixed-sex tents - this is all about God, writes Fionola Meredith.

For many young people, the muddy debauchery of a summer rock festival feels just like heaven. Freed from the restrictions of home or school, the thought of spending three sweaty, joyous days with their mates, all pie-eyed on cheap cider and sleepless nights, seems irresistible.

But for Ireland's Christian youth community, the hedonistic pleasures of the average rock festival just aren't an option. Instead, this weekend, thousands of young Christians will flock to the Summer Madness festival, at the Kings Hall in Belfast.

Aimed primarily at 15-24-year-olds, Summer Madness is Ireland's largest Christian festival, offering a packed programme of rock music, worship and debate. After its tentative beginnings in 1987 as a Church of Ireland youth event in Castle Archdale Country Park, Co Fermanagh, this year organisers expect more than 5,000 visitors to show up between today and next Tuesday.

While the vast majority of festival-goers are from the Protestant tradition, Summer Madness has always been keen to welcome those from all denominations as well as none.

"Even in the very early years, it was broadly based," says festival director, John Kee. "That cross-community dimension was always present. These days, we get between 300 and 400 young people coming up from the Republic, and we estimate that 10-12 per cent of participants are Roman Catholic. Then there's an overseas contingent of about 200 people, from Brazil, Chile, Singapore, Holland and South Africa."

Summer Madness shares many of the same ingredients as mainstream rock festivals. Noisy guitars, ecstatic dancing and staying awake far into the night will certainly be on the agenda. But the festival's ground rules are unequivocal: there won't be any smoking or drinking, and unless they happen to be married, participants can forget about mixed-sex tent sharing. (In fact, the rules specify that tents must be at least two metres apart, presumably to lessen the temptation for midnight liaisons.) Stringent child protection policies are in place, and no young people are accepted on to the site unless accompanied by a youth leader.

Since attending Summer Madness means strictly one person per sleeping bag and nothing stronger than an energy drink, what's the big attraction?

Susanna Kernahan (18), from Co Down, says: "Summer Madness is one of the coolest things in the Christian calendar - there's a great sense of community there." But what does it offer that big Irish rock festivals like Oxegen or Slane don't? "It has God in it. Even if God isn't important to some people at the start, He will be there by the end."

Kee explains: "Our experience is that young people come to the event hungry for a spiritual focus, keen to deal with the issues that pertain to their daily lives. When it comes to seminars and debates, sex is on the agenda every year. It gives kids a forum for discussion away from the slightly more greenhouse atmosphere of their own church; they don't have to sit and squirm in front of their local minister."

This year, in addition to debates about creationism, racism and Aids, youngsters will be offered tips on "living in a 'sexplosive' society when you're young and hormonally charged". It's the openness about difficult issues that's a big part of Summer Madness's appeal, says David Porter, director of the Belfast-based Centre for Contemporary Christianity in Ireland. He has spoken at festival debates several times over the years.

"Other Christian youth events can be a bit buttoned-up and uptight, but Summer Madness is more loose and congenial, more open to where contemporary culture is going. The perception is that it isn't rigidly controlled by adults. In that sense, it scratches where it itches. A whole range of trendy vicars have made it the bright spark that it is."

Greg Fromholz is definitely one of the "trendy vicar" posse. He works as youth director for the Anglican diocese of Dublin and Glendalough, and is also a "creative consultant" to Summer Madness. But he says that all the fun and praise and worship counts for little if participants don't translate that euphoria into direct action in their own communities.

"Summer Madness is the largest faith-based initiative in the country. It's a big bang, but if there's nothing to follow it, there's no point."

That's a view shared by tousle-haired God-rocker Tre Sheppard, frontman of successful Christian band 100 Hours. Summer Madness regular Sheppard - his slogan is "big guitars, big voice, big heart" - will be a main-stage speaker at the festival. He says, "It's what happens afterwards that's important. There's this catalytic thing where young people work and hope together; it's really powerful what they can achieve. And the church must engage with pressing social need; where there's pain, where there's need, we should be doing something about it."

That's why both Fromholz and Sheppard are brimming with enthusiasm for the StreetReach project, which follows directly after Summer Madness. According to organiser Linda Gordon, "StreetReach's message is simple: to take the love of God in practical ways to the people in the most broken areas of our city. How do we do this? Go into any of the eight StreetReach areas this summer and you'll see young people cleaning streets, delivering window boxes to pensioners, painting over sectarian murals, chatting with refugees . . . This year we are working in 15 areas across Belfast and are planning to bring more than 1,000 teenagers from both sides of the community on to the streets."

Heather McCormick (19), from Belfast, who has been attending Summer Madness for five years, will be leading a StreetReach team this year. "It's about putting it all into practice, as opposed to hyping everyone up then sending them back where they came from," she says.

Not all young Christians are attracted to the earnest intensity of Summer Madness. One former participant found it all a bit overwhelming, describing it as "an evangelical version of the Nuremberg Rally". But with tickets for this year's festival already sold out, it seems that young Christians across Ireland just can't get enough of, as they say themselves, "hanging out in God's presence".