The sound of $20 bills ripples like the impatient tapping of fingers. A bookie stands at the door of an off-campus apartment building, his baseball cap turned backwards. To any passerby, it's nothing more than a couple of students meeting for fun. But despite appearances, there is business to be done.

It's time to pay up, as they say in the gambling business - big business at the University of Arizona.

More than a few students find themselves visited by these bookies on a regular basis; drawn into the circle by friends, roommates or word of mouth.

The bets start out simple, a quarter on Florida State, 50 cents on the Trojans, but they soon rise to more than $1,000.

This kind of gambling is only a fraction of what can be found in every office, classroom or residence hall on campus.

Most people can control the habit, but like alcohol or drugs, there are always those who become addicted.

John Katzen, business senior, has seen the darker side of gambling first hand. He ran himself into a small debt before deciding to give it up.

Others, he says, have gone much farther.

"Gambling is a drug," Katzen said. "It's a high. It's like a bong hit.

"Some people can do it to have fun. Others become addicted and they have to do it. You have Gambler's Anonymous just like you have Alcoholics Anonymous."

The dangers of a gambling addiction are just like the risks of any other addiction. The gambler gives in to a strong habit which eventually becomes a dependence.

This dependence sometimes causes alternative behaviors, including criminal activity. Not only is the gambling itself a crime, but debtors then often turn to other forms of crime in order to pay off a large debt.

Katzen, who began gambling when he came to Arizona, says bookies encourage the habit.

"They call you on the phone or give you the lines on the upcoming games," Katzen says. "They let you know there is money to be won."

Money is just the surface cause of the addiction, but it is often the charm that pulls people in. After the addiction becomes a reality, the money serves only as a status symbol.

No matter how well a gambler is doing, the chance at gaining more is overwhelming.

If a gambler is down, he or she is "chasing" to get back in it. In either case, it's a cycle many gamblers cannot break.

"I know about 20 people who gamble through bookies on campus," says one UA student, who wished to remain anonymous.

"It's usually about $100 and if it's a good bet you start upping it - up a thousand, down a thousand just like Vegas. It's a habit they can't stop."

Sources say there are at least five major bookies on campus. Clients establish credit lines with their bookies that generally run from $200 to $2,000. After the games a bookie will usually set up an appointment or send a "runner" to the gambler to either collect the money or pay off what they owe. A gambler who cannot pay is usually given a payment plan until a debt is paid. Once that is done the bookie can decide if they will give a client more credit or not.

Yet, despite the apparently large amounts of money being thrown around by students, administration and student government have failed to recognize any serious problem.

"Honestly I haven't heard of the problem and I would be surprised at how much it is going on," says Saundra Taylor, vice president of Student Affairs.

"I can imagine that for some students it is out of control," she adds.

ASUA President Ben Driggs doesn't see the problem either.

"I really don't know of any incidents on campus," he says. "Maybe I've heard a few things in class, but it's something that I haven't come across."

Campus police are also unaware of any gambling epidemic. Sgt. Brian Seastone of the University of Arizona Police Department says that in his 15 years at Arizona, he has never been involved in a campus gambling bust.

The question still begs an answer. If students who gamble or used to gamble acknowledge that there is a problem on campus, why isn't it generally noticed?

Taylor suggests an answer.

"There is so much in our culture that condones gambling," Taylor says. "It is legalized in Las Vegas and I don't think you hear a lot of people who are disapproving. But it's a dangerous addiction that can deplete a student's resources."

Taylor says administrators plan to look into the student gambling problem, as well as creating counseling services. Currently there are no services provided for gamblers at the university, but the Gambler's Anonymous chapter in Tucson helps several university students.

Student gamblers often blur the line between harmless fun and a serious addiction with gambling.

Patrick Moran, business and public administration senior, says he gambles for recreation, but he knows others go much further.

"Most people I know bet among friends, but the problem is definitely out there," Moran says. "Some guys really get into it. I have a friend who would lay down $100 or $200 a game.

"For me, I got into gambling in order to put my money where my mouth is," he adds. "It's a matter of backing up your team by being willing to bet on them."

For gamblers, college football bowl games are where most of the action takes place. But almost any sport is available come playoff time.

The Super Bowl is the last game in a string of big money bets. Bookies offer shots not only on the final score, but on the first team to score, on the following scores each quarter, and even on the coin toss.

Sports isn't the only gambling addiction available for students. With the introduction of casinos in Tucson and Arizona over the last few years, students can play Las Vegas-style games almost at their doorsteps.

"I know a lot of people who are heading out to the casinos now," Moran said. "I don't know if it's a fad, but I know of people dropping money there."

Student gambling is not uncommon on campus, and for most people it is nothing more than a hobby.

But for a few, it can become more serious than that.

For the bookie it's a lucrative business; for the gambler it's a dangerous addiction.