School's out -- or almost. And everbody's looking forward to those golden days of dolce far niente , But doing nothing isn't always sweet, and once you've gotten over the thrill of not having to pack lunches and drive car pools, you'll wish you had signed your kids up for that course in rock-hunting or cartooning or singing in musical comedies. If you get on the stick and sign up now, your kids can experience architecture or make a movie about the zoo this summer instead of just twiddling their thumbs and driving you crazy. Here are some ideas for programmed summer adventures:

At the Corcoran Gallery of Art, kids from four to seven can swish, swirl and splash -- with paint -- in a week-long workshop July 21 through 25. For the same age group, there are also week-long morning workshops in sculpture (August 4 through 8) and costume design (August 18 through 22). Kids from eight to eleven can experiment with watercolors (June 23 through 27), sculpture (July 7 through 11), design (July 14 through 18), drawing the inside and outside of the Corcoran (July 21 through 25 and August 4 through 8), printmaking (July 2, through August 4), and papercraft, from oragami to collage, (August 11 through 15). Fee for all Corcoaran workshops in $35 for members; $45 for non-members. Call 638-3211, extension 45.

Paper is also the subject of a course called "Snip, Rip, and Crinkle" offered to four-through nine-year-olds by the Smithsonian Associates from July 14 through 18. Fee for the one-hour-a-day course is $18 for Smithsonian Associate, $24 for non-members.

In other Smithsonian associate courses, four-through six-year-olds can study vertebrates at the Zoo and the National Aquarium (11:30, July 21 through 25), and dramatize folk heros such as Pecos Bill and John Henry (10:15, July 21 through 25). In "I Wish I Were a Fish," a 1 1/2-hour course to be held July 14 through 18, four-to nine-year olds will make their own aquariums and study the residents. The seven- to nine-year-old set can also sign up for a course called "Whales, Sea Lions and Seals," which includes trips to the zoo. Sundays, 10:30 to 12, July 13 through August 3. Fee for all the above courses is $18 for Smithsonian Associates, $24 for non-members.

Kids from seven to 12 can zoom in on the Zoo, in an on-location film-making course that includes research on the animal subjects. The two-hour course runs from July 14 through 18 and costs $30 for associated, $38 for non-members.

Kids from eight through 13 can produce, star in, and tape their own TV shows in a 1 1/2 hour course offered Saturday mornings from July 12 through August 2. Sessions will include interviewing the mounted Park Police and acting out scenes form most- and least-favorite TV shows.

A five-day, two-hour-a-day course in rock-hunting, with field collecting trips, is offered seven- to nine-year-olds (July 21 through 25) and 10- to 12-year-olds (july 14 through 18).

Bob Webber, creator of Moose Miller, will reveal the secrets of comic-stripping to kids 10 to 15 in a two-hour course offered July 14 through 18. Ten- to 15-year-olds interested in drawing air- and spacecraft can learn drafting from a NASA artist in a two-hour course scheduled for July 21 through 25. Fee for those and the above courses is $30 for Associates, $38 for non-members.

The mysteries of calligraphy will be unveiled to 10- to 15-year-olds in a two-hour course offered July 21 through 25 (fee: $36 for Associates, $46 for non-members). Wildlife photography, with excursions to the Zoo and to the banks of the C&O Canal, is open to kids 13 to 15 in a Saturday course to be held July 12 through August 2. Fee is $27 for Associates, $35 for non-members.

To register for Smithsonian coursed, call 357-3030.

Fourth- through ninth-graders will be introduced to computers in a course at the Beauvoir School, June 23 through July 11 or July 14 through August 1. Fee for the halfday program, in which each student will spend half an hour a day working with a computer, is $200. Eight- to 12-year-olds will interview real authors in another Beauvoir course called "Authors in Action." Then the kids will write and illustrate their own stories and, after a visit to a printing and binding plant, produce their own books.

Kids from 8 to 12 who prefer movies can study film-making at Beauvoir, producing their own movies for a special parents night. Fee for these six-week sessions, which run from June 2o through August 1, 9 and 3, and include swimming and sports, is $485. Call 537-6599.

Teens from 13 to 15 want to immerse themselves in the arts or just get one foot wet should look into the 1 1/2-hour afternoon sessions at the Capitol Hill Arts Workshop. Monday afternoons from July 7 through August 22, from 4 to 5:30, the subject is wearable art -- macrame, sewing, tie-dye and jewelry. Tuesdays the topic is acrobatics and on Wednesdays teen can pot and sculpt. Thursdays the dance floor is reserved for modern and jazz dancing instruction. Fee for one class is $32; $102.40 all four. Call 547-6839.

Kids of all ages are welcome to join an Art in the Summer Program run by Gillian Rozicer and Susan Weiss at Rozicer's home at 3212 Stephenson Place NW. The course runs from 10 to 12:30, June 30 through July 11, and includes outdoor sketching, drawing, painting, clay, weaving, tie dye, jewelry, puppetry and model-making. The $50 fee includes materials and snacks. Call Rozicer at 966-0595 or Weiss at 946-2305.

At the Zoo, four- to six-year-olds will sand-cast seals and make mountain gorilla mosaics in a course called Animal Arts and Crafts. Each class will begin with a visit to the quarters of the animal subject. There are two sessions available: weekdays from July 7 through 11 or Saturdays from July 12 through August 9, all from 9:30 to 11:30. Fee is $24 for Friends of National Zoo; $30 for non-FONZes.

Kids from seven to nine can get to know "Your Web-Footed Friends" at the Zoo in a course offered Saturday mornings from 9:30 to 10:30, June 28 to August 2; $20 for members, $26 for non-members. In a course called "Monkeys, Lemurs and You," 10- to 12-year-olds will meet their fellow primates. The class meets in the Lions Den, 9 to 11 on Saturday mornings from June 28 through July 26. Fee is $26 for members, $34 for non-members.

A five-session photo workshop, using the Zoo inmates as subjects, is open to 13- to 15-year-olds. The class meets Saturdays from 9:30 to 11:30, from July 12 through August 9. FONZes pays $20, non-members $28.

For all Friends of National Zoo courses, call 232-7700.

Summer is good time for kids to get back to nature. Seven- to 12-year-olds can join a junior naturalist club at Long Branch Nature Center, 625 South Carlin Springs Road, Arlington. At press time, there were openings in the Tuesday-through-Friday four-day sessions July 22 through 25, July 29 through August 1, and August 5 through 8. Each session will include nature crafts, field trips and animal and plant identification. There is no fee and preference is given to Arlington County residents. Call 558-2742.

Budding actors and actresses can use the summertime to polish their drama skills. At Adventure Theater in Glen Echo Park, six- to 12-year-olds can sign up for two-week Creative Arts Camp sessions geared toward building "characters." Programs, from 9 to 3 Monday through Friday, cost $100 for two-sessions beginning July 7, July 21 and August 4. For ages 13 and up, there's a four-week theater performance workshop culminating in a public performance. The course will include script selection, costuming, lighting, sound, set construction, choreography, makeup and acting.

And kids 15 and older can produce a puppet show under the direction of Allan Stevens, director of the Smithsonian Puppet Theater. The class at Adventure Theatre, Monday evenings 7:30 to 9:30, June 9 through August 4; the fee is $66. Call 320-5331.

The McLean Stage Studio offers a two-week course in Children's Theater Training for six- to eleven-year-olds. The session runs from June 16 through June 27, 1 to 2:30, at the McLean Baptist Church. Fee is $75. Call 893-6806.

Kids who prefer musicals can audition for the Round House Theater's children's musical theater lab. Pre-schoolers through seventh-graders learn and rehearse Saturdays, 2 to 5, at the theater in Wheaton beginning June 28. They'll show what they learned in public performances August 9, 10, 14 and 15. Fee: $35. Auditions will be held June 18. The Round House Theater also has beginning and advanced drama courses for fourth-graders through teenagers, including a resident camp on the Hood College campus. Call 468-4172.

Arts Day Camps sponsored by the Round House Theater let first- through sixth-graders choose their own major: clowning, puppetry, pottery or film-making. You can choose a Rockville or a Bethesda location and one of three Monday-through-Thursday, 9:30 to 2:30 sessions: June 30 through July 10, July 14 through July 24, July 28 through August 2. It's $68 a session. Call 468-4172.

High-school students can experience architecture in intensive two-week workshops at Catholic University. Students will visit architects' offices, analyze the buildings of downtown Washington, examine solar energy and design their own buildings. Sessions run from July 7 through July 18 and from July 21 to August 1. Fee is $235 and the number to call is 635-5191.

High-school students who want to improve study skills can learn how at the George Washington University Reading Center. The course runs from July 14 through July 25, and both morning and afternoon sections are available.The fee is $130, and the phone number is 676-6286.

GWU also has a summer enrichment program for creative kids who just can't get enough to read. In "Books Alive," second-through eighth-graders will read, talk about what they've read, and interpret great books in performances in schools and libraries. The course will meet June 23 through July 11, and the fee is $350. Call 676-6286.

Bright kids entering grades five through nine can use the summer to learn about computers as a tool for urban planning. Led by a professor from GWU's Urban and Regional Planning Department, the kids will explore an urban environment, use computers to analyze the data they have gathered, and use the analyzed data to create their own urban environments. Class meets at the university June 23 through July 11 from 1 to 4. Fee: $350. Phone: 676-6286.

Summer is also a good time for togetherness -- not the sit-around-the-house-and-stare-at-each-other kind, but the do-something-together kind. If this is your bag, consider one of the parent-child courses offered by the Smithsonian Associates. There's animated film-making for kids ages six to eight (parents can be any age); magic, including a parent-child magic show at the end of the course (for kids ages eight through 12 plus one parent); exploring the Smithsonian Museums (ages four to six) and folkdancing (ages six to nine). These are weekend courses. For details, call 357-3030.

At the Smithsonian's Chesapeake Bay Center in Edgewater, Maryland, parents and pre-schoolers (three to five) study ecology together. The theme of the course is waterways, and it includes exploring the estuaries and creeks and looking for the plants and critters that live there. The class meets Tuesday mornings from 9 to 11, July 8 through August 5, and costs $35 per child, with one or both parents. Call 261-4190.