CHICAGO -- Nearly six decades after graduating from college, Pete Shannon still can't get enough of lectures and homework assignments.

The 78-year-old Dallas retiree has taken dozens of classes at his local community college since he stopped working as a CPA in 2004. This summer he studied music composition, and in the fall he plans to tackle philosophy and whatever else piques his interest.

Exams can be challenging, but one thing he doesn't sweat is tuition bills. In one of many such arrangements across the country, Dallas County residents age 65 and over get up to six hours' tuition free at Richland College every semester.

"It's a marvelous opportunity,"

Shannon says, calling the college his "candy store." "It's a wonderful place to go. The catalog is rich with all kinds of classes."

From continuing education and enrichment classes to graduate school, many retirees are pursuing their interests at the college level.

It's a trend that is likely to grow as seniors' ranks swell with baby boomers looking to either acquire new job skills or simply enjoy new learning experiences.

The prospect of having to pay for even moderately priced college classes might sound daunting to a retiree living on fixed income. But numerous discounts, tuition waivers and other deals make it possible.

"There are more opportunities than in the past for senior citizens to take college classes and get help paying for them," says financial aid expert Mark Kantrowitz, publisher of FinAid.org and Fastweb.com.

Many community colleges and some four-year colleges allow seniors to audit classes for free and significantly reduce tuition for those who take them for credit. The financial arrangements vary widely by school and so do the age requirements, generally 60, 62, or 65 and over.

Twenty-one states and Washington, D.C., offer free tuition for senior citizens at some or all of their public colleges, according to FinAid.org. The student still must buy textbooks and may have to pay fees.

Two relatively new opportunities offer even more help.

The Senior Scholarships program, created last year as part of the Edward M. Kennedy Serve America Act, provides $1,000 education awards for people 55 or older who volunteer 350 or more hours a year. The money may be used for the volunteer's own education or transferred to a child, foster child or grandchild.

And the American Opportunity tax credit can lower taxes for students of any age dollar-for-dollar for the first $2,000 spent on tuition, fees and course materials. The credit also applies to 25 percent of the second $2,000. Unless extended, the temporary credit expires at year's end.

More seniors might head back to school if they knew about the deep discounts and freebies -- or lived near colleges. As it is, education remains an untapped resource for most.

According to data released in June by the Bureau of Labor Statistics, Americans from age 65 to 74 say they spend 6.77 hours on leisure and sports on a typical weekday, watch 3.58 hours of TV, spend 0.71 hour reading, 0.59 hour socializing and 0.03 hour on education. That's less than two minutes, compared to 0.46 hour or about 28 minutes for the population as a whole.

Shannon, who got his undergraduate degree in business economics from Rice University in 1953, is happy to stay in school for life. He says he takes college classes to get out of the house, at his wife's urging, and exercise his brain.

The rest of him gets a workout, too, as he often bikes the 4 1/2 miles to campus.

A perfect 4.0 grade-point average through 114 credit hours shows he's not taking any mental shortcuts.

"I like writing the papers and doing the work," he says. "It's more complete than Googling a subject. And by the time you finish the semester, you've learned something."

Thanks to the tuition deals, he reckons he has spent no more than $1,000 on education expenses since he retired. But he'd dig a little deeper into his retirement savings if he had to.

"Frankly, I'd go to college even if I had to pay up to $1,000 a year for it," he says. "I'd consider it part of my personal entertainment budget."

If retirement-age students decide to borrow to pay for college, loans don't have to be as burdensome as they might expect.

Federal student loans are discharged on the borrower's death. That means the retiree student's heirs won't get shortchanged because of those late-in-life classes in history and Chinese. The senior also can choose the repayment plan with the longest payback period, thus the lowest monthly payment.

When finances aren't an issue, most any educational experience is still possible in retirement.

Anne Carter Harrison-Clark of Williamsburg, Va., is thriving as a 71-year-old student at the William & Mary Law School.

Learning more about the law is something she long aspired to do during a career as a lobbyist and public policy lecturer at Georgetown University, among other roles. Now she has both the time and money to do it, thanks to she and her husband Bob selling property near the top of the market six years ago.

Immersed in her third year of law classes, she is thrilled to be studying at the college where her great-great-grandfather, Benjamin Harrison V, a signer of the Declaration of Independence, was educated. She doesn't at all mind being the only white-haired student or getting constantly asked why she's there.

The short answer to that is she wants to keep the brain cells going with new information and new contacts. And she doesn't know where this educational "journey" will take her, although she does intend to get her law degree at some point, on her own schedule.

"This whole (college) experience has been like dessert, like double fudge icing on a cake. Just a wonderful experience," says Harrison-Clark, who already has a Ph.D. in politics. "I highly encourage it."