The lucrative business of campus speeches.

So, it's college commencement season—the time when hapless parents and siblings sit patiently through three-hour graduation ceremonies. For them, the only saving grace may be a snappy graduation speaker. But how does a college snag an Oprah or a Jon Bon Jovi for their students' big day?

On rare, fortunate occasions, a school administration can call on alumni contacts and pull a high-level string. But most celebrities—even the ones who don't take cash—won't stop by out of the goodness of their hearts alone. Elite universities often entice speakers with honorary degrees and awards. But the irony here is that large universities with big endowments like Harvard or Princeton—the ones that actually could afford to pay for their speakers—usually don't have to. The allure of a fancy title is enough for many. Once reserved for a particular achievement, the honorary degree has evolved into a means of eschewing cash payouts.

Which raises the third option: money. While a famous speaker like Bill Cosby will often waive his fee—which Michael Frick, president of Speakers Platform, estimates hovers above $75,000—not all celebrity talkers are so generous. And with "mid-range" speakers pulling in obscene amounts of cash for their typical engagements, a nonwaived fee can prove prohibitively expensive. Yet even in these cash-strapped times, many colleges are willing to dole out megabucks for the right speaker. Georgia Gwinnett College has only been open for three years, but the school shelled out $9,000 in security fees for U.S. Army General David Petraeus to speak at its graduation this year. When former New York Mayor Rudy Giuliani spoke at High Point University's 2005 graduation, NPR reported that the appearance could set the school back about $75,000.

Why do schools do it? To be impressive, mostly, says Frick, an expert in the industry. Big names draw big attention—and, sometimes, donations. Frick says a famous name can, in some instances, inspire alumni to donate. When an alumnus hears about a prestigious speech at the ol' alma mater, he or she might feel compelled to chip in, said Frick.

Smaller, private colleges are perhaps under even greater pressure to bring in a celebrity speaker; after dropping a mound of cash on their child's private degree, parents expect to see someone noteworthy.

Roping in a superstar can also backfire. University of Oklahoma drew a massive amount of unwanted attention when it handed over approximately $110,000 to hear Katie Couric speak. Couric didn't come out smelling like roses herself. Yes, the funds came from a private donation. But even so, this scenario begs the question: Why didn't this private donor put the cash toward a scholarship fund? And with the flak the university received, can it really count on a flood of subsequent donations?