A long time ago (the days before cheap flights), in a city far, far away (by road, at least), a young, earnest Irishman found a job paying £2.50 an hour, for a 10- to 12-hour day, in a theatre. Actually, it wasn't a theatre, but an old, rambling building that was pretending to be a theatre "complex".

Anyway, he was happy. He swept the floors, and tore tickets, and helped clean up the bar when the last punters had gone home at 4am. Sometimes, he got to slip into the theatres and see shows for free! He was very happy. Even though most of them were awful.

Then one day, a theatre company from his hometown arrived. He tore tickets for their show, and slipped inside and sat at the edge of a row. Their play was very beautiful, but it didn't make a lot of sense.

The first 40 minutes were a little vague. Somebody got up to leave, and the earnest Irishman glided over to the door to make sure it opened and closed as quietly as possible, so as not to disturb the performers. The performance, after all, was very intense.

The next 20 minutes were still a little vague. Somebody else got up to leave, and he tiptoed over to the door again to smooth their exit. Ninety minutes came and went. There were fewer and fewer people left in the audience, but at least the stream of departures was less disturbing to the performers, thanks to the young man's efforts.

Eventually, the show ended. The three people left in the theatre were very appreciative. Afterwards, one of the actors approached her countryman, who had been attentively helping people leave quietly.

"What the hell were you doing?" she roared at him. "Jumping up and down like that! Every time someone left, it looked like two people were leaving! What kind of idiot are you?"

(Perhaps that was when the earnest young man decided to forsake a career in the theatre, and become a critic for the Sunday Tribune. The theatre company, meanwhile, went on to greater things.)

The Edinburgh Fringe is a rite of passage for anybody passionate about theatre. Like most rites of passage, it is sordid, smelly, uncomfortable and accompanied by self-abusive amounts of drinking. And it is fundamentally ridiculous: why would anyone design a festival consisting of over 2,000 shows, in 250 venues, with almost 20,000 performers?

The answer is: they didn't. The Edinburgh Fringe is the artistic triumph of the laissez faire principle.

Unlike our Dublin Fringe Festival, which is curated, the founding principle of the Edinburgh Fringe is freedom: the only criteria for entry is finding a venue and letting the Fringe HQ know in time to be included in the programme.

Think of it as turn-of-the-19th-century New York, and the performers as refugees from the old world. For those who are successful, it offers great riches: a Fringe First award by The Scotsman newspaper, or other high-profile award, guarantees full houses and the attention of agents and producers. West End bookings and international tours beckon (as with Enda Walsh's Disco Pigs, 10 years ago). But for those who fail: ignominy and squalor.

The vast majority of those 2,000 shows will play to audiences consisting solely of
the theatre staff and any
family who've travelled; with
the company members likely
all sharing a damp bedsit
and surviving on beer and cornflakes, it can get pretty gruelling.

The Fringe is the free market of theatre, but not only do you have to fight to get your audience into the theatre, you also have to fight to keep them there. The Edinburgh audience is notoriously restless – for every show a punter chooses to see, there are half a dozen others on at the same time they could
have seen. And they won't be
shy about rushing out to try
and catch one of them if your show doesn't grab their attention.

The Fringe press office counts 57 Irish shows at Edinburgh this year, including comedy and dance. One of the hottest will be Enda Walsh's New Electric Ballroom (featured here recently), which the London Times has already declared one of the 20 "must-see acts" this year.

Ballroom is one of 13 shows being supported by the government funding agency, Culture Ireland, which is spending €300,000 and hosting a networking event during the festival to promote Irish work.

That will focus on international promoters, says the agency's head, Eugene Downes, helping the Irish companies make personal connections that, combined with the impact of their work, may get them valuable invitations abroad.

But Downes has some more prosaic insights into making a success of the Fringe. "The timing of shows is crucial," he says. "Ninety minutes tops – 60 to 70 minutes is a bonus.

"The title of the show needs to make an impact." (He references Joanne Mitchell's Living with Johnny Depp.)

And a good review isn't enough. If a show gets one, they need to "photocopy it, and flyer it like hell".

"Edinburgh is absolutely rough," he says, clearly relishing the thought. "It's the toughest, most competitive, most Darwinian arts festival in the world."

The corollary is that, for those who make it, "it can be the great breakthrough".

What follows are some of the most interesting Irish acts on this year: some will be looking
to secure their status as Edinburgh faves, others
looking for that breakthrough. (They all say they just want to put on a good show, and entertain people, but they'll
find the competitiveness pretty all-consuming when they get there.)

A last word of advice to them: no matter how squalid and ruthless it gets, be nice to the fella tearing the tickets. You may be neurotic about getting a good review this year, but you'll be looking for them again in the future. And you never know, he could have something to do with it.

1 Terminus

Mark O'Rowe's plays could be made for Edinburgh: short, arresting, violent and utterly idiosyncratic. 'Howie the Rookie' was a hit there in 1999. "We had people queuing around the block", O'Rowe recalls. That play starred Aidan Kelly and Karl Shiels, and the three had a "debauched" time. "It's wild over there", he says. "I'd dread doing something like that again…" He's older now, a family man, and – crucially – he has the backing of the national theatre, which secured a prestigious slot in the Traverse theatre, the home of new writing on the Fringe, a venue which practically guarantees its shows will get critical and public attention. 'Terminus' had a great popular reception (but a mixed critical one) in New York earlier this year; Edinburgh is likely to be more receptive to O'Rowe's poetic, fantastical, violent, graphic-novel-in-monologue.

At the Traverse Theatre until 24 August

2 Eco-Friendly Jihad

Abie Philbin Bowman went to the Fringe as a journalist in 2005, and saw 30 shows in a week – less than 2% of the festival, he notes. He realised there were certain elements you needed for an Edinburgh success: crucially, "you have to be able to sell your idea in 10 seconds". He had an idea, and returned the next year with a comic monologue about Jesus returning to
earth, trying to get into the US and being sent to Guantanamo. He sold out, and toured to the West End, Boston, and Pakistan. With everything to lose, he returns this year with a show about an environmentalist so frustrated with the failure to reduce carbon emissions that she joins al-Qaeda. It's comedy with an agenda; so far, Edinburgh agrees.

At Underbelly until 24 August; www.abielaughs.com

3 Fregoli Theatre Company

For all the celebrity comedians and star venues that more or less guarantee you'll see something good by somebody with a reputation, the beating heart (and growling bowels) of the Fringe are the students. Galway company Fregoli, formed by former members of UCG's Dramsoc, are trying their hand this year, bringing two shows, 'Tape' by Stephen Belber and 'The Maids' by Jean Genet. Maria Tivnan is disarmingly modest, and realistic, about their objectives. "We want to see how we can sell a show, and live together in a really small space."

The cast for each show (which have successive runs) will do the publicity work for the other. They'll have 8,000 flyers and a collection of paper-flower badges themed on 'The Maids' that they're making themselves as a further gimmick. They're also planning to busk, with a street act based on their concept for 'The Maids', which has the actors tied together with six-foot lengths of material. They'll learn, alright… they've spent €6,000 so far, and are planning a fundraiser in Galway for 8 August.

At Rocket @ Demarco Roxy Art House, 11-23 August; www.fregolitheatre.com

4 Forgotten

Fishamble have been quietly touring Pat Kinevane's elegiac dance-theatre piece, inspired by his experience of working in an old folks' home, for over a year. They'll be back at the Belltable in Limerick and Mermaid in Bray in November. In the meantime, they play just four nights at Edinburgh, in Scotland's national dance theatre, Dance Base. That won't allow time for the traditional word-of-mouth or review-inspired success, but no matter: director Jim Culleton hopes they will have sold out the 100-seater venue in advance. This is one of the shows championed by Culture Ireland, and the short run will give Fishamble ample opportunity to showcase the work to international promoters and presenters, who flock to Edinburgh seeking work for their venues and festivals. Kinevane's piece, which mixes bracing Irish monologue with Japanese Kabuki dance, and is fired by real social anger, has already played in Paris, Prague and Sibiu in Romania.

At Dance Base, 20-23 August

5 Irish Cream

Dance Ireland has collaborated with Dance Base in Edinburgh to present a triple-bill of Irish dance shows, 'Irish Cream', plus a showcase featuring two more. Catapult Dance bring 'Beatbox Bingo', inspired by "the perplexing world of office politics". Fearghus O'Conchuir brings 'Match', a duet originally created for film, shot on the turf at Croke Park, and now being taken indoors, and Legitimate Bodies Dance Company bring 'Hanging In There', which "deconstructs the Good Friday agree­ment", apparently. On 21 August, a special showcase (supported by Culture Ireland) will give Rex Levitates and Ponydance (who produce the best publicity pics ever) a chance to strut their stuff at this prestigious dance venue.

At Dance Base, 6-16 August (not every day; check dates)

www.edfringe.com