SINCE 1974, Fort Dupont has played host to a variety of summer entertainment, free. Every Saturday and Sunday at 8:30 p.m., an average crowd of 20,000 to 25,000 people walk, roller skate, drive, bike, piggyback or run to a hole in the woods in Southeast for a couple hours of fun. This weekend through the last weekend in August, a whole family can picnic in the park, without paying for baby sitters or gas, stretch out and take in Washington's laid-back summer scene.

The National Park Service sponsors the entertainment available at Fort Dupont, which includes local and big-name performers of disco and jazz music, children's theater, modern dance and, new this year, gospel music. The idea of a community-arts program began six years ago when Al Dale, director of the Fort Dupont Summer Theater program, felt the need to provide entertainment for low-income families right in their own community. Since then, the people in the neighborhood have seemingly adopted the entertainment and recreational facilities available at Fort Dupont as their own, and have cooperated with Mr. Dale and the Park Service in suggesting ways that the influx of weekend theatergoers might be more easily accommodated, although adequate parking remains a problem. But District and Park Service police will also be cooperating to ensure, among other things, that cars do not block neighborhood driveways.

Last year, an estimated total of 450,000 people attended the concert series, evidence that the summer scene at Fort Dupont is enjoyed by residents citywide, and even more people are expected to spread their blankets this year because of higher gas prices. Fortunately, cuts in the federal budget have had no visible impact on the summer theater program, since this year's budget was approved last year, before the budget cuts were made. But next summer's budget may be in doubt. There is no reason why it should be, however, and there is every reason for the Park Service to continue funding Mr. Dale's popular and very successful community-arts program in the forseeable future. Especially with unemployment so high among black teen-agers in the area, Fort Dupont seems an excellent way of giving positive direction to jobless and perhaps restless youths on summer weekends. Providing free entertainment for these youths will not touch the unemployment problem, but it will provide many of them a sorely needed social outlet that may help to make everyone's summer a little more entertaining and enjoyable.