"Dance. Why?"

"Um. I heard it was great."

"From whom?"

"Em. The publicist. And the company director."

"Oh great. You'd better bring me for dinner beforehand."

"I can't. It starts at 6.30."

"Why does it start at 6.30?"

"Because it's four hours long."

THERE was a real risk that This Dancing Life would be the straw that broke the camel's back. The camel is long-suffering and, being eight-months pregnant, her back is already bearing some strain. Recent weeks alone have seen our holidays interrupted to spend a night on Cape Clear tracking an improvised dance project by an Israeli choreographer and an evening at a documentary about the making of a play about an allegorical novel by Nobel Laureate Jose Saramago, in Portugal, in Portuguese. (Worse, the director made a speech beforehand, so we couldn't sneak out, even when we realised it was awful. ) But there is a saving grace to This Dancing Life. You may come and go as you please.

It's extraordinary how liberating that simple concession is.

The 20 or so dancers, too, seem liberated. When not on the floor, they lounge at one end, drinking from water bottles and stretching. Some are barefoot, others wear runners. All are in their own clothes.

Sara Rudner, the choreographer, a small, intense-looking woman in tracksuit pants and hoodie, sits at a table at one end of the hall, barking out the titles of scenes. "Lori's Layered Breakdown!" "Peggy Solo with Company!" "Skating Dance!" A banana skin lies on the bench beside her, a bag of nuts and a sports bottle sit on the table. She laughs a lot watching the dancers.

She takes to the floor during a scene entitled 'Post-Performance Discussion', where she takes questions while dancing. Asked about working with this company, Irish Modern Dance Theatre, she says, "My favourite thing is that they do things I have never thought of. They constantly surprise me." She dances with surprise and pleasure. She is magnificent, a dance raconteur.

Gradually, a general pattern emerges.

There are carefully choreographed ensemble dances and sequences that look like improvised rehearsal exercises. There are solos and duets. These all overlap and merge, so that solos emerge out of the ensemble; structure emerges out of chaos, and then dissolves again. There is music, some of the time, in a bewildering array of genres, played live by two musicians equipped with a comprehensive world music toolkit.

After 40 minutes or so, I take a short nap, stretched back on the table that serves for my seat. We take a stroll after about two hours and go the Spar. A girl in the audience stands up to stretch. I get a mild cramp, but manage to deal with it without shouting.

The minutes and hours flow by gently. I had a fear of dance, of not knowing the vocabulary, the critical context, of not knowing how to watch it or how to write about it. But, three hours in, that is all gone. There are dancers, and there are us. Sometimes the movement is beautiful, sometimes it is funny, sometimes it is jarring. There are moments when it is irritating or seems self-indulgent, but they are passing. I find myself looking forward to individual dancer's solos.

It seems like dance music: the various sequences like samples, being mixed by a DJ/choreographer. Slowly, incrementally, expertly, Rudner cranks it up, taking us with her. It builds and builds until, in the final sequence, any structure dissolves into a glorious mass dance-off.

One crucial inhibition remains in place, however: none of the audience dances, perhaps to our shame.

And then, suddenly, it ends, leaving one of our friends to say she is surprised it's "over so quickly". The audience rises to its feet and, belatedly, the barrier between company and audience dissolves, as it becomes quickly obvious that almost all of this small audience is related to the dancers.

This Dancing Life must come back. It played for just two nights in Dublin and one in Kilkenny. That's not enough for word of mouth to counter the understandable bias against a four-hour dance show. Everybody should see it, even long-suffering camels.