This is a city of nightclubs, but the night life is something else these days, and not just because of the feverish edge sharpened by the war last summer.

At a Halloween party at the C-Lounge in Beirut, some danced on the bar and competed in a contest for the title of sexiest woman. (Kate Brooks/Polaris, for The New York Times )

Nov. 02, 2006- By 8 p.m., women in their 20s and early 30s are prowling in packs of five and six, casting meaningful glances at any and all passing men. In the bars the women dance for hours - often on top of the bar - and legs, midriffs, bare shoulders and barely covered bosoms are offered for public admiration.

Samir Khalaf, a professor of sociology at the American University of Beirut, said the scene astonished his American colleagues. "They are just shocked," he said. "'This is Lebanon, the Middle East?' they say. They can't stop talking about all the belly buttons, about all these highly eroticized bodies. You see it everywhere here, this combination of consumerism and postmodernism and female competition."

For a few weeks twice a year, after Ramadan and before Christmas, thousands of Lebanon's young men return from jobs abroad - and run smack into one of the world's most aggressive cultures of female display. Young women of means have spent weeks primping and planning how to sift through as many men as possible in the short time available. The austere month of Ramadan ended a week ago.

The country's high rate of unemployment pushes the young men to seek work elsewhere, sometimes in Western countries like France and Canada, but mainly in the United Arab Emirates, Saudi Arabia and the other oil states on the Gulf. The women, inhibited by family pressures, are generally left behind.

"The demographic reality is truly alarming," Khalaf said. "There are no jobs for university graduates, and with the boys leaving, the sex ratios are simply out of control. It is now almost five to one: five young girls for every young man. When men my sons' age come back to Lebanon, they can't keep the girls from leaping at them."

For the men, who return with deep pockets and high spirits, the holiday welcome is gratifying.

"In Doha it is completely impossible, because you can't talk to women in the Gulf," said Wisam Hamdan, 35, back from Qatar, where he manages hairdressing salons. "But Lebanese girls are very friendly. I am hoping to meet lots of girls, and then I will pick one."

The other night Roula Hallak, 27, was wandering the bars of Gemmayzeh, an eastern Beirut neighborhood, with a troupe of six meticulously dressed and made-up girlfriends.

"I'm not looking, but she is, and so is she," Hallak said, poking two of them, who giggled and declined to give their names. "It's so hard to meet the perfect guy this way, but there are so many out in Beirut at this time of year. You go out and you look and you're always hoping."

According to Khalaf, Lebanese Christians have been migrating for economic reasons since Ottoman times. But as the nation's economic crisis has deepened, the exodus has come to include young men from all religious groups and across the socioeconomic spectrum, as well as a tiny but growing number of young women.

Over the past two decades, the Gulf has become the economic pole, and its pull has only grown stronger since the monthlong war this summer between Israel and the Hezbollah militia in Lebanon. With the political situation here still so uncertain, investment and work opportunities are growing even scarcer, and the gender imbalance worsens.

For young women here, dressing fashionably is a competitive game; stare- down contests between young women in restaurants and malls are common.

Kareen Yazbek, a Beirut psychologist, says that the lack of available men is a constant theme in her discussions with young women recovering from depression and drug addiction.

"Throughout my practice, the main issue that comes up with many young women is that they can't find anyone to be with or to marry," Yazbek said. "Among college-age girls it's not such a problem, but after graduation there's a big change as the men start seeking work outside of Lebanon."

"The social pressures on young women are just huge," Yazbek continued. "The focus is more and more on being beautiful, on pleasing other people. The competition is intense, conformity is a big thing, and everyone, rich and poor, gets plastic surgery. You can go to parts of Beirut where almost every young woman has the same little nose."

And the big prize, all seem to agree, is the attention of one of the visiting native sons.

"The guys that remain in Lebanon are the stupid ones!" exclaimed Nayiri Kalayjian, 19, who was hitting the bars on Monot Street, in central Beirut, with three girlfriends.

"We're too good for them," she said. "The ones who remain in Lebanon are the ones with closed mentalities, the ones who just want a virgin girl. You start to feel that the men who stay in Lebanon are the ones with no ambition in their work, and so you wonder, why are they still here?"