NEW YORK, NOV. 30 -- The madness of it all. They were trying on ball gowns in the aisles, housewives from New Jersey in bras and pantyhose. "Look, I've only got 2 1/2 hours to shop, I can't talk right now," said a woman trying on hats. "You understand, honey." They were so serious, so driven. Outta my way! They didn't even see Calvin Klein standing at the door, cool in black loafers and white socks. Calvin at a sample sale!

"I couldn't care less," snorted Stacey Brosnan, a nurse and rock singer from Manhattan. "I came to look at his clothes, not him." The singing nurse didn't bother with formalities either -- she slipped a Klein skirt right over her black leggings outside the dressing room. "When you go to as many sample sales as I do, you have to be prepared."

But this was no ordinary sample sale. Today's first round of shopping at Seventh on Sale, a weekend marathon of shopping to benefit those stricken by AIDS, produced such a spending frenzy that the six checkout lines were backed up the length of the selling floor at the 69th Regiment Armory. "We had figured it would take a minute to a minute and a half to check out each customer," said Jeffrey Cohen, president of Ralph Lauren's retail division, which coordinated the sales force. "But it's taking twice as long. We didn't expect people would be buying as much as they are."

At the preview party Thursday night, when designers were buying each other's clothes, the registers rang up $380,000 by the time the last partygoers left shortly before midnight. Tickets for the dinner raised more than $1 million. With 13,000 shoppers expected over the weekend -- paying $10 apiece for 2 1/2 hours of shopping -- Seventh on Sale could raise an estimated$3 million to $4 million, according to Carolyne Roehm, president of the Council of Fashion Designers of America. All proceeds will go to the New York City AIDS Fund.

The first wave of 1,500 shoppers descended on the Armory at noon today, almost oblivious that Roehm, Klein, Donna Karan, Louis Dell'Olio and Vogue's Anna Wintour were waiting side by side to greet them. Armed with white plastic bags given out at the door, they made a beeline for the booths and, like contestants in a supermarket shopping spree, started stuffing their bags with Anne Klein pants, Donna Karan bodysuits and Ralph Lauren sweaters. What they couldn't stuff, they carried over their arms, over the handles of baby strollers. One young man was walking around with a large plastic duck under his arm.

"It's a lamp," said Matt O'Grady, a demographer, holding up the duck. "Isn't it great? And only 20 bucks at the Macy's booth." He planned to put it next to his pink flamingo lamps. "We have a bird motif at our house."

Jeanne Gallagher flew in from Cleveland for both the sale and the gala dinner Thursday night. "It's unbelievable," she said. "I've seen all these designers. And they're so friendly too!" Gallagher wasn't exactly uncharitable herself: She and her sister, Kathy Miller from New York, together spent $8,500 on Thursday night alone. "We ended up with six bagfuls," sighed Gallagher. "I got a dress and a suit from Bill Blass, two cashmere sweaters from Donna Karan, and let's see. ..." Who knows. She and her sister were making another pass at the Blass booth, in case they overlooked something.

Lynn Klein was standing in the middle of the Armory, under a canopy of 45-foot birch trees hung with pink paper lanterns. She had a red Maud Frizon shoe in her hand. "Only $35. Can you believe it?" said Klein, an American Airlines flight attendant who flew in from Miami on a $6 employee plane ticket. "I got them at the Vogue booth. The other booths were so crowded I couldn't get in." She also acquired a leopard-spot belt, a Saint Laurent sash and a broken fingernail. "I wouldn't mind all these people, but I'm about to lose my fake nail," she said, wiggling the damaged finger in the air.

By 2:30 p.m., when the first shift was supposed to end, the last of the big spenders staggered into line. Beaded gowns, shoes, cashmere sweaters -- the unwanted -- lay in heaps near the dressing rooms. Shoes were out of their boxes. Calvin Klein's booth looked as though it had been ravaged by locusts. And to think, there were 11,500 shoppers still to go.

Outta here!