The young suburban couple was searching for an inexpensive evening out. Instead of grabbing the entertainment and dinning guides, they reached instead for a university catalogue.

They found it was cheaper to sign up for a weekly anthropology class than to pay for a once-a-week movie and dinner. Plus they were fascinated by anthropology.

That is just one example of the "quiet revolution" sweeping America's campuses, says Dean Robert Hawkes Jr. of George Mason University's Division of Continuing Education.

More and more adults are enrolling in college, says Hawkes, and they are changing the nature of higher education. This comes at a time when the number of younger students is declining. If the trend continues, the 18-to-22-year-olds who once made up the overwhelming majority of the student body may find themselves in the minority.

The 40-year-old in jacket and tie no longer stands out as an oddball in a sea of Levis. Colleges and universities are actively recruiting the older student, male and female, to fill up the lecture halls.

At George Mason, says Hawkes, where at least 35 percent of the 12,000-member student body is participating in a continuing-education program, the average student age is now 279

Hawkes distinguishes the "quiet revolution" from the "turbulent, very vocal and very visual" sit-ins and other disturbances in the late '60s. This latest change, he believes, "will have an even larger impact -- and a better one."

George Mason in Faifax City is one of more than 40 Washington-area educational groups celebrating Adult Continuing Education Week through Friday with information booths and fairs scheduled in the District of Columbia, Maryland and Virginia.

The theme is "Education . . . To Be Continued," to promote the idea that learning if lifelong "both in and outside the classroom."

Courses range from such traditional undergraduate- and graduate-degree subjects as English and American history, to noncredit self-help or self-improvement classes in "Personal Problem Solving," Money Management" or "Basic Carpentry," to physical fitness for senior citizens.

As part of the change, classes are going where the students are. George Mason alone offers courses at 25 to 30 sites in Northern Virginia, including many high schools.

A professor of U.S. southern history, Hawkes -- Virginia-born and with a drawl to go with it -- recently taught a course on the History of the South, since 1865 to neighborhood residents in an Alexandria school.

The majority of adult students, says Hawkes, are 25 to-35-year-old professionals "who are beginning good careers." If married, both spouses are working. Usually they have no children, or are just beginning a family.

They've enrolled for a variety of reasons:

To expand on their undergraduate degree with additional training in, for example, computers; to obtain a master's degree; to get the college education they've always wanted; for personal enrichment; or, in the case of many housewifes, to brush up on academic skills before seeking an out-of-the-home job.

The impact of so many older students on campus has been enormous, says Hawkes.

"For the most part," he says, they "are incredibly good students." He sees this as a healthy development in education "for everybody," including professors and 18-to-22-year-olds.

"Think of the perspective adults can bring to class -- how helpful to the students around them. It's fun to see the questioning idealism of the younger students, interacting with the wisdom, experience and even the skepticism of the older ones."

Older students' competitiveness, he says, appears to have contributed to the reversal of grade inflation. From time to time, professors have had to adjust their grading standards because of the high quality of adult-student performance. "And that's very salutary."

They've brought "disciplined study back to the classroom after the 1960s, when there was experimentation, but a failure to take into consideration the human desire to be challenged."

Older students, unlike some of the younger ones, he says, "know how to diagram sentences, put the commas in and do their assignments."

And older students want their money's worth. When the professor lets the class out early, the 18-year-olds "are delighted" at the free time. The adults, however, complain. "I paid my money for that," they tell the administration.

They are also "aggressive and assertive" in letting educators know the kinds of courses they want. As a result, "they have forced educators to look more carefully at the education they are providing."

When George Mason began evening classes for adults in 1973, says Hawkes, "we had difficulty finding faculty who wanted to teach. Now, I believe, the majority prefer a class with adults -- it's more challenging and more demanding. They want the kinds of students who can turn classes into demanding graduate seminars."

Because the university recognizes adults have many outside commitments, it offers clases in three-hour (7:05 to 9:50 p.m.), once-a-week blocks so "they can have the other nights free for the family or to study at the library."

Acknowledging the demands of that kind of regimen, Hawkes says, "I have a lot of respect for the person who after a full day can come and sit through three hours of class. It takes a determined student."

While many adult students already have their degrees, classes are available for those who may not have completed high school.

"And if you flunked out of college 10 years ago, we'll give you another chance," says Hawkes. "Those 10 years have probably given you a wiser, wider life experience."

Hawkes likes to think of continuing education as the "pioneering force in higher education. As adult-populated campuses become the norm, he envisions the development of "new types of learning."

He already is dreaming of the day when commuters will take Shakespeare courses by cassette tape as they ride the Metro to work.