By 11:20 a.m., Rich and Barbara Craig were down to their last $20, and things were looking bleak. For 15 hours, the same slot machine had been spinning and spinning and spinning -- chewing through $1,000 of their cash -- without giving up a nickel in return.

It was the second day of their frustration. They had arrived at the Charles Town Races and Slots casino the previous morning at 7 and got stuck trying to win the jackpot from this particular machine. By the time the slot machine automatically shut off at closing time, 3:30 a.m., they were out too much money to give up and go home to Pennsylvania, an hour and a half away.

So they drove up the road to a shopping mall parking lot, slept in their Ford Explorer for three hours and then went right back to that dark and smoky corner of the sprawling complex filled with 2,700 slots, stuffing the very same machine with $20 bills and spinning to win a payoff known as the "lobster pot."

This casino in the eastern panhandle of West Virginia is within miles of three neighboring states -- Pennsylvania, Virginia and Maryland -- and each week, it draws thousands of players from those gambling-free jurisdictions. The possibility of billions in tax revenue has Pennsylvania and Maryland contemplating legalization of slot machines, and Maryland Gov. Robert L. Ehrlich Jr. (R) considers them essential to closing a $1.3 billion budget shortfall.

For now, however, Charles Town and the lure of the big win will remain a mecca for such people as Rich and Barbara Craig. But by the second day, Barbara was feeling fairly drained as she went to look for more cash shortly before noon. Other than the meatball sub at a Sheetz gas station convenience store at 4 a.m., complimentary coffee from the cocktail waitress at 8 and a few bites of a 3 Musketeers bar, Barbara had had nothing to eat.

At the cashier, Barbara asked for a $500 advance on a credit card. Then $400. $300? Okay, $100. Sorry, she was told; she'd maxed out her cash advances.

She made her way through the sprawling Slot City to tell Rich, 51, the bad news when the tall and placid man with graying sandy hair became about as animated as he gets. He'd played a different slot machine and hit a jackpot. He handed her $553 in crisp $100s, $5s and $1s. They were back in business.

Barbara, 52, sat back down at her slot to play a game known as Barracuda. She tossed back her long, bleached blonde hair and lit a Marlboro Light 100 with particular disgust. Her hazel eyes drooped. She'd slept in her maroon sweatpants and gray sweatshirt. And, without a toothbrush, she said it felt like a train had run through her mouth.

"I'm so exhausted. This is stupid. I'm stupid," she said. "We're just piddling our lives away in here. This is no life. After today, this is it. We're not coming back."

She bet 45 cents and mashed the red play button. Bright oranges, plums, cherries, sunfish, barracuda and seahorses rained down the video screen. Nothing.

Unlike the traditional three-reel slot with one pay line, Barracuda -- one of the newer generation of video lottery terminals -- has five vertical lines, three horizontals and a total of nine confusing lines, straight across, V-shaped and, as Barbara calls it, the "cocky way" to bet and win on.

There are interactive bonus rounds. And, most alluring of all, a jackpot, or "lobster pot," that climbs up incrementally with each spin and can promise a hefty payout. To win, all three little lobsters with smarmy smiles must show up and click their tails as tinny Caribbean steel drums play.

"I don't really understand the mathematics," she said. "I just know when it lights up, I've won something."

All around in the dim, endless night of the club, the hazy air was thick with the sounds of nickels and quarters clinking and coughing as they methodically dropped into metal bins. Machines dinged and buzzed and trilled with jackpots. Leopard Spots played a jungle drum riff, Alien Attack a deep basso organ note. And the Barracuda machines played a 12-note marimba tune with every spin. The noise was deafening.

"This is like drudgery," Barbara said. Then her eyes lit up. Two lobsters. And a third's antennas poking up from below. "Oooh, just like they say, one away, one away," she said.

Roger Ramey, vice president for public affairs at Charles Town Races, says he's never placed a bet or spun a slot in his life. But, he said, he sure approves of the people who do.

"Jefferson County here gets about $4 [million] or $5 million a year for doing nothing," he said. "Meanwhile, we got an ambulance service we never had. And five little cities get little checks on Wednesday, so they're able to meet their budgets without scratching around."

There's no question there's demand. At 6:45 a.m. on a snowy winter Thursday, six people were waiting for the casino doors to open. In the summer, there are often hundreds waiting, said Craig Butts, head of security. That's one of the reasons they're adding 800 slot machines this summer. By state law, the slots have to pay back 80 percent of what they take in. Charles Town's slots average closer to a 90 percent payout, Ramey said.

About noon, Rich stood over Barbara's shoulder in the blue glare of the video slot, chewing on a plastic coffee straw, watching her spin. Mr. Kim, a fellow nickel slot player, came to say goodbye. He'd been with them at closing the night before, gotten a cheap motel room and come back by 7 a.m. to try to hit his lobster pot.

"I give up. I'm tired. I got a headache," he said. He'd gone through $600 that morning.

Barbara was becoming despondent. Play. Three cherries. Three points. Play. Two clams. At 2:15, she hit what many would consider the jackpot -- five barracuda in a row. Because she'd bet low to conserve money, she won 5,000 points, or $100. But they weren't playing for barracuda. They wanted the lobster pot.

"That gave us some play money, honey," Barbara said to Rich.

"We need it," he said.

"What do you want me to bet now?" she asked.

Like most regulars, each had a complicated system. Some players never change their bet, worrying that any variation may anger the ghost in the machine. Others swear by worry stones. The woman playing behind Barbara rubbed the screen before each spin.

The truth is, nothing a player does can change the odds at a slot machine. A random number generator in the machine's software is what determines where the lobsters will fall. And when.

"Every spin is completely random from the one before. There's a chance you could win the highest jackpot two or three times in a row, and an equal chance that you could sit there all day and not win one cent," said Steve Williams, product director for Spielo, manufacturer of Barracuda and the PowerStation machine, assembled in June in tiny Sainte-Anne-des-Monts in Quebec, to which Barbara was glued.

"There's mathematical truth," he added. "And then there's gaming truth. It all depends on whether you believe in the gaming god or not."

It's an open secret that gaming directors often program slightly different odds into certain machines. Lore has it that the more public the slot -- near an elevator, an entrance or a cafe -- the more a slot will pay.

At 4:20 p.m., Rich and Barbara's machine was up to 16,751 points.

Play. Nothing. Play. Nothing. Play. Three oranges for 20 points. Play. Nothing.

With every spin, scientists say, Rich's brain was giving him a hit of euphoria-inducing dopamine. Blood rushed into the anterior cingulate region of the brain, flush with neurotransmitters that react to expectation and reward. It took just 265 milliseconds for his brain to register his loss, set up the expectation that next time he was sure to win and make him decide to press again.

Ten minutes and 71 spins later, the lobster pot had inched up by 42 points, and his neurotransmitters were on a roller coaster of dopamine.

He and Barbara take that ride three or four times a week, driving down from Shippensburg, Pa. They met a few years ago when both were drivers for a heroin treatment center. They found they both loved the Bible and soon married.

When they retired about a year and a half ago, the days loomed long. Their pygmy goats, box turtles and dogs needed only so much attention. So they came to Charles Town for the heck of it -- and discovered lobster pots.

"We wish we never had," she said.

Now, they keep blankets in the car in case they need to stay overnight, something they've done nearly a dozen times. They swear they won't get stuck trying to recoup their losses from a particular machine. They try to set a budget, but they never stick to it.

"It's not that I'm consumed with it, but you feel so guilty that you put all that money in, you have to keep playing just to break a little even," she said, hiking her boots onto the next seat. "You can't beat the machine, yet you're driven. There's that little thing in the brain. Oh yeah, greed. I guess that's what causes people to become addicts."

Financially, they're all right, Rich said. They own their house on 12 acres. Their kids are grown. And altogether, they may have been out a couple thousand dollars last year.

But they both want to end this life, mesmerized by the spin of electronic fruit and sea creatures.

"We were going to try to find something better to do. Fishing. Going to auctions. We used to love to go to auctions," Rich paused. "That's two things."

At 7:30 p.m., they balanced minestrone soup and cold pizza on their laps at the machine, and Rich took over the spinning. Barbara wandered over to the Winner's Gift Shop and stocked up on tiny crystal and gold-plaited fairies, eggs and umbrella decorations, glassware, mini Elvis slot machines and hand-held electronic games for future Christmas presents. She had enough credits for $300 in merchandise -- the reward for spending $6,000 gambling in the past few months.

As she wound her way back at 7:55, Rich sat, slumped and still in the raised chair in front of the slot. The lobsters hit. A floor attendant counted out $912.45 into Barbara's outstretched hand. "Wow, that's a big one," she smiled.

It had taken them nearly 30 nonstop hours. They'd spent $1,400. They were drained. And their win meant only that they hadn't lost quite so badly. They were out only a couple hundred bucks. "Right now, I just feel relief," Rich said.

Within minutes, they'd packed up and were out in the snowy parking garage, ready to head home. "I need to go and apologize to the dogs," Barbara said. They'd put the cats in the bathroom and scattered dog food on the floor so their dachshund could get exercise looking for it.

"I keep telling myself, we are not going to come back," she said. "At least through March."

The Craigs finally spin a win with five barracudas for a payout of 5,000 points -- $100.After playing for several hours on the same slot machine, Barbara and Rich Craig of Shippensburg, Pa., pause to consider the prospects."I'm so exhausted. This is stupid. I'm stupid," Barbara Craig says. "We're just piddling our lives away.""I don't really understand the mathematics," says Barbara Craig, 52, of Shippensburg, Pa., her husband, Rich, 51, behind her. "I just know when it lights up, I've won something."