School was in session for about an hour when Daniel Kreiger decided to put together a Mork and Mindy jigsaw puzzle. Five other students huddied nearby over a fast-paced dice game.

"Last year we didn' have to do much work," said Kreiger, a fifth-grader, as he worked the pieces of the puzzle. "The windows in our school building were low and if we had nothing to do we jumped out of them. Once, me and my friends jumped out consecutively 18 times."

Kreiger is one of 15 elementary school students at the PartridgeBerry School in Laurel, a "free school" where the students decide when, if ever, to study, what subjects to concentrate on and how to spend the day.

Products of the 1960s atmosphere of social change and experimentation, "free schools" -- with names like Sprout House, Osh Kosh and Different Drummer -- reached a peak of popularity in the early 1970s. Most of them have vanished in the last few years, the victims of diminishing funds and wanting enthusiasm.

At the height of the movement, there were more than 350 "free schools" of various sorts in the country, about 25 of them in the Washington area. Today, their number here has dropped to six or seven.

The enrollment at PartridgeBerry dropped by half this fall, and the school probably will close in June, according to Joyce Koelling, one of the parents who has helped run it.

"It was the burn-out," said Koelling, explaining the school's demise. "parents did this on their own time and they've gotten exausted. All of these efforts from the 1960s and early 1970s are dying out. The people aren't out there anymore.

Like PartridgeBerry, most "free schools" were organized by parents -- often liberal, upper-middle-class and white -- as an alternative to what they considered the overly regimented and confined atmosphere in the public schools. The "mass production" approach to education, as one parent put it.

In the public schools, "kids are bored and marking time and learning a lot about how to sit down and shut up," said Ann Anderson, who ran the now-defuncty Free School Clearing-house, an information center for the area's alternative schools.

Anderson said the schools developed because of a "combination of frustrations with the public schools and an interest in the new life style changes going on at that time (late 1960s). People wanted to bring their kids up in a different way."

That "different way" eliminates class rooms, examinations, scheduled class periods, report cards and required activities. Students spend time doing anything that interests them, be it studing, playing board games, talking with friends or roaming outside.

Krishna Dorney, a fifth-grader at PartridgeBerry, for instance, said she was only interested in playing during her third grade, so that is exactly what she did. "I've gotten interested again and I'm working to catch up to my level. I read adult science fiction books mainly," she said.

On the day that Daniel Kreiger was trying to put together the Mork and Mindy puzzle, two other students worked on ratios with one of the school's two teachers.

The five other students rolling the set of dice across the open classroom from Kreiger were playing "Buy and Sell," a money game that also teaches basic mathematics.

As two 6-year-old boys looked at a math book by themselves, one turned to the other and said, "I don't like this page." They flipped to the next page, oblivious of a dog and guinea pig wandering nearby.

The only "requirement during the PartridgeBerry school day is a morning meeting, where the day's "options" are discussed, and a final clean-up session. m For the first time this year, the older students are required to spend a half hour on math and another half hour on "language skills," which could mean reading a magazine.

Robert Skenes, who has studied several free schools across the country, described the "free" education system as "self-directed. You allow people to become little entrepreneurs in terms of deciding what they want to do in school.

While this philosophy was popular -- and sold many books -- five or 10 years ago, in the years since it has lost out to the new emphasis on "basics" and competency testing.

"An education which allows people to do what they want, when they want, as the spirit moves does not work for the bulk of the people. Children do need structure, do need the basics," said an assistant superintendent in the Prince George's County public schools.

"A lot of people came away distrusting the free school movement," said one former activist. "Sometimes their kids slipped through the cracks, and did nothing but play.

Mary Dutcher, a teacher at Amazing Life Games, a pre-school in Northwest Washington, acknowledged the problem. "There is a risk that people take in sending their kids to free schools, that they won't learn to read, write and add as we all did in public schools, But that's an unfounded fear."

It is apparently a risk that fewer and fewer parents are willing to take in the search for quality education for their children.

"The strange thing about it is these schools really met the need of people at that time. But when the people changed, moved or became disenchanted, the schools died," said Anderson.

As another former free school teacher and supervisor put it, "Times have changed. When the free school movement flowered there was a lot more optimism about creating a beter alternative and there was a feeling among teacher (and parents) that we knew what was wrong and could change it. I don't think anyone's that certain anymore.