UNIVERSITY PARK, Pa. -- For a week or more, nearly 700 dancers, all of them college students, swore off most of the vices Penn State has to offer. They changed their typical college junk food diet, made sure to get plenty of sleep, avoided caffeine and nicotine. They even pledged not to drink.

All to get to this point, when after 48 hours, their limp, sleep-deprived bodies collapsed onto the floor in unison, signaling the end of Penn State's 33rd annual Interfraternity Council/Panhellenic Dance Marathon, known as THON.

The event presents a startling degree of self-sacrifice, but when the dancers sat, they could take satisfaction in their accomplishment, the culmination of a yearlong effort to raise money to help children with cancer.

They stared up toward a stage and saw the children who are beneficiaries of The Four Diamonds Fund, the organization supported by THON that helps to cover unpaid medical expenses for pediatric cancer victims.

The children were the reason for the aching feet and knees, and with the 48-hour marathon complete, the children held the tangible result of the dancers' commitment on 11 poster boards, with numbers drawn on each.

Slowly and deliberately, they held up each number, revealing the total raised this year: a THON record $4.2 million.

A crowd of about 10,000 onlookers who were packed into tiny Rec Hall cheered wildly, while some dancers cried and others struggled to stay awake.

In a hellish 48 hours meant to symbolize the daily agony of those undergoing treatment for pediatric cancer, dancers are not allowed to sleep and rarely permitted to sit while constantly battling mental and physical obstacles.

It is a powerful and unique mission, and it has allowed THON to raise money from sources as small in scale as grass-roots "canning" trips to cities and towns across Pennsylvania -- you've probably seen the students collecting money at an intersection near you -- to large corporate sponsors like Pontiac and Apple Computers.

Many of the dancers tended to look at it in a simpler context: They were providing a weekend of fun and welcomed distraction for the 160 families with cancer-stricken children who traveled to State College.

"You can look at THON as two things," said Molly McShain, 22, of Philadelphia, "as something we do to have something to show for all the money we raised, or as an event we throw for the families who need some distractions from some serious trials."

Around 3 p.m. yesterday -- four hours from the conclusion of the marathon -- "Family Hour" was held. Despite the 44 hours the dancers had been up, it marked a high point in their moods.

Arms interlocked as the hour began. Some would occasionally loosen their grip to wipe away tears.

A speech by Katie Austin -- a high school senior, cancer survivor and Four Diamonds beneficiary -- provided particular poignancy. To a crowd of at least 5,000 dancers and observers, she told her story of leukemia diagnosis at 12, the remission of her illness thanks to THON and her plans for a future she wouldn't have otherwise seen.

"When it came time ... to think about college," she began, her sobs oddly making her voice more authoritative, "I only applied to one school."

It was followed by a video montage honoring The Four Diamonds children who lost their battles, and the introductions of every family in attendance.

The hour helped steady the 694 dancers, some of whom ached or became nauseous or even delusional.

Attempting to balance the highs and lows are "morale-ers" assigned to each dancer. Wearing distinctive yellow shirts, they provided encouragement and a helping hand for dancers crashing under the psychological stress of the marathon. For every six hours they spent pepping up their dancers, they were given four hours out of Rec Hall.

If they were lucky, the morale-ers typically spent an hour of that time with eyes closed, which was supposed to keep them upbeat enough to encourage their dancers when they started to swoon in the early morning hours yesterday.

Like when Melissa Rae Brown's hot, swollen feet dropped into a bucket of ice around 4 a.m. yesterday, and her teeth clenched together in anguish.

"It's just like such a striking pain," she said, making it sound like a hot dish cracking when run under a cold faucet. "I wouldn't normally cry from putting my feet on ice, but when you're this tired..."

The 22-year-old from Bucks County trailed off, stumbling uneasily on her strained foot arches and aching knees. Her boyfriend, Mark Sablowski, 22, of Churchill, steadied her.

"But you have to consider," she continued, "that this is just for two days," while the sick children and their families face pain every day.

"You have to fight the selfishness."