It's like a scene from a bad horror movie. People stagger through the streets of the capital in the early hours of the morning having poured out of nightclubs, unfocused, with ghoulish faces.

Some are crouching in doorways and some are leaning against anything stationary for support. Others congregate outside fast-food restaurants, cramming burgers and chips into their mouths and then discarding the wrappers among the heaps of litter strewn about.

The taxi queues are enormous and many choose to begin their journey home on foot, hoping to pick up a cab along the way. Outstretched arms try to hail down every passing vehicle.

In the light, the women's make-up is smeared from perspiration produced in heated clubs from hours of constant dancing. The men, without the comfort of touching up their faces, look jaded and have wet hair.

The competition in the market means nightclubs try their best to get young people to part with spending money in their venues. Happy hour and drinks promotion nights, such as Tuesdays in the Kitchen, where shots of vodka are sold for £1, are a hit with students and younger club-goers. If the clubs don't try to entice people in with alcohol, then the drinks companies do. Beer companies put on promotions in various pubs, offering patrons a free drink with every pint or two they buy. Clubs also do special offers to bring their numbers up on weekdays - student nights, women's free-in nights and free entry for those before 11 p.m.

Earlier on in the night the scene is a different one. At 10 p.m. in Fireworks, on Dublin's Pearse Street, there are various aromas of men's deodorant and women's perfume at each of the four levels. The club is so new and exciting-looking from the outside, with neon lights and garish chandeliers, that nobody minds queueing or getting hassle from bouncers, protective of the new venue's reputation.

"Of course I'm over 23. What age did you think I was?" protests one young woman. A metal stairway, wide, open bar space and the thrilling early-night atmosphere greet the club-goers. Some lounge on the leopard-skin couches, others prefer to stand and chat in big groups. Bottled beers sit on the tables with mobile phones and packets of cigarettes. Everybody seems to be smoking.

The women admire each other's clothes. Backless tops, halter-neck dresses and straight slacks go well with the fresh make-up. Men stand in crisp, sleeveless shirts surveying the scene. No one dares to take to the dance floor yet, but by about 12 p.m. in the Palace on Camden Street the lower dance floor is packed.

The crowd is distinctly young, with some in their early 20s but many more still in their teens. The bouncers on the door check some identifications but the tall women with skirts and high heels and the good-looking, clean-shaven men never seem to have a problem getting in. Three gardai stop everyone coming into the club. "Were you here two weeks ago?," one asks and ticks her clipboard when the answer is no. "Was I what? I thought they were going to ask for ID," says one young woman later in the toilets.

People dance in close groups and when Robbie Williams's latest song comes on, the dance floor fills with bodies, all singing along to the words of Rock DJ. Those sitting down talk excitedly over vodkas-and-orange and pints of lager. Some have had too much to drink already, with one young man staggering to the toilet and another sitting on a racing car display holding his head. "In the summertime the place is full of 16- and 17-year-olds off school," says one 19-year-old woman from Kildare. "I hate it. You sit here watching them falling all over the place, spilling their drinks all over you," she adds. But she says things will get better now that the schools are back and the colleges are starting up again. The venue mostly attracts young students from the DIT in nearby Aungier Street.

In Club Anabel in the Burlington Hotel, the two young women who have been dancing beside their drinks say their 16-year-old sisters go to the Palace. They say they wouldn't go there because, at 22, they would feel intimidated by the younger women. "Plus they get so overexcited," says one of the women.

Their parents don't mind their younger siblings going out as they have raised older children and have given up the fight to keep them in after 9 p.m. "She doesn't even lie about it. My sister tells my parents where she's going out to."

Their parents are nervous about them going out because of recent trouble after nightclubs but say that isn't going to keep them in at night. Management in the Palace insist they check for identification and only accept one of four types of identification - a legitimate college ID, a passport, a full driver's licence or an official age card. "People who come here have to have proper ID or they won't get in," says one bar manager.

THE crowd in Anabel's is of a mixed age, though the age profile drops on student nights on Wednesdays. Tonight, there are young people in their early to late 20s, but there are also older men and women in suits and sophisticated clothing. Those dancing sing along to the words of songs which are played all day on the radio.

A group of young men stand watching those on the dance floor with drinks in their hands. "I have never been here before but my friends have. They wanted to pull so they came here," one of the group, in his mid-20s, says.

Another young man, who has just finished a degree in UCD, says things have changed since he began college. "Before, students would go out on a Thursday night. Now its every night of the week."

By 1.45 a.m. the POD is heaving. All hands are raised in the direction of the DJ at the top of the club. The tiny dance floor is jammed with people moving to the interminable dance beat. There are no groups of friends dancing together and no Britney Spears tracks are played. Instead, people dance alone, all facing one way. Some go back to their seats after a while and sip their Red Bull and vodka. Others just reach for some bottled water and keep dancing.

"I would go out usually on Thursday and Saturday," says one young man dancing beside the bar. Even though the club finishes at about 2.30 a.m. he doesn't mind going into work the next day a little groggy. "It's no problem, I do it all the time," he says.

As the music gets louder and more intense the crowd shout and clap, goading the DJ on to quicken the beat. When the tempo reaches it pinnacle, lights flashing from all directions, the music moves back to its original rhythm and the dancing intensifies. People pound the air with their fists, with sweat running off their faces.

When the music stops and the lights come on most head for the cloakroom and leave. Some stragglers remain, too drunk to move and abandoned by their friends.

Outside, people make arrangements for the following night. Voices are hoarse from shouting over the loud music. Will it be Anabel's, the Vatican, the Redbox or the Kitchen? Whatever the choice, the streets will be filled with revellers again the following night, all eager to sample the delights of what the city has to offer.