LAFAYETTE, La. — Their homes are bursting with guests. Their schools are overwhelmed. Traffic has been at a standstill for three weeks.

But the capital of Cajun country still knows how to party.

Throngs turned out yesterday for the first full day of the Festivals Acadiens, billed as the largest Cajun festival in the world, in a show of just what "joie de vivre" means.

"This festival has always been, even in good times, a festival of cultural survival, and we're surviving again," said Barry Ancelet, who co-founded the event 30 years ago. "It's our social instinct when things go bad."

The sun beat down fiercely as dozens of couples two-stepped around a field to music so upbeat and bouncy it was hard for anyone not to tap a foot.

Sweat dripping off them, dancers did a series of three close shuffle steps and kicked their heels on the popping off beat. Smiles bloomed as the Savoy Family Band reeled and wiggled across the stage.

Older couples ate picnic lunches in the few spots of shade and tapped their feet in time, while children raced around Girard Park, banging on rub boards and twirling to the wheezing accordions.

Snatches of French wafted through the crowd over plates of jambalaya.

"Cajun music comes from deep down inside, and it's a very passionate music," Terry Huval, a member of the Jambalaya Cajun Band, said as he awaited his turn on stage.

"It's passionate if you're singing a sad song. It's passionate if you're singing a happy song. It's like riding in a cart without a driver. You never know where it will take you."

The festival's slogan — "Still Standing" or "Toujours Grand Debout" — pays homage to the 250th anniversary of the Cajuns' expulsion from Novia Scotia in 1755 by the English and their eventual migration to south Louisiana.

The story of the expulsion — "Le Grand Derangement" — is one Cajuns know by heart and of which they are fiercely proud. A copy of the English expulsion order and a list of all the names of the families who fled French Canada were printed on the back of the festival's poster.

"With everything that's happened, we're still here. We're still going to go on with life," said Kelly Strenge, spokeswoman for the Lafayette Convention and Visitors Commission. "Cajuns look like they're celebrating all the time. It's just the way we handle things."