Children can go on a hayride and watch blacksmithing and other colonial craft demonstrations this Saturday at the annual fall festival of the Rose Hill Children's Museum, just north of Frederick.

On Sunday, the Montgomery Ballet performs excerpts of "Cinderella" for children at the Trolley Museum near Wheaton. This performance is outdoors, so families are advised to bring blankets or lawn chairs.

The following events are free unless otherwise noted.

CEDAR HILL -- Open daily, 9 to 4, 1411 W St. SE, Anacostia. Cedar Hill, Frederick Douglass' home, recalls his work with films, interpretive exhibits and a house tour. 426- 5961 or 426-5962 or 426-5963.

USS BARRY -- Open daily, 10 to 5, Washington Navy Yard, Ninth and M streets SE. The Navy destroyer's weather deck is open for public viewing and self-guided tours. 433-3377.

CAPITAL CHILDREN'S MUSEUM -- Daily, 10 to 5, 800 Third Street NE. Sunday, noon to 7, "Family Festival." Celebrate the opening of the museum's new Nek Chand Fantasy Garden, which houses about 50 tons of sculpture from India. Throughout the day there'll be Indian music and food will be on sale. $2 admission. 543-8600.

DOLL'S HOUSE AND TOY MUSEUM -- Tuesday through Saturday, 10 to 5; Sunday, noon to 5, 5236 44th St. NW. A collection of antique dollhouses, dolls, toys, games and an exhibit of antique cat games and toys. Adults $2; under 14, $1; group rates available. 244- 0024.

NATIONAL COLONIAL FARM -- Tuesday through Sunday, 10 to 5, 3400 Bryan Point Rd., Accokeek. Sunday, 1 to 4, learn colonial woodworking techniques using traditional tools. Adults $1; children under 12, free. 301/283-2113.

RAILROAD STATION MUSEUM -- Wednesday through Saturday, 11 to 4; Sunday, noon to 5, Main Street and Maryland Avenue, Ellicott City. The renovated station has a diorama of the trip of Tom Thumb (an early 19th-century train) from Baltimore to Ellicott City. There are also sight and sound shows, model train exhibits and tours of the museum. Adults $1.25; under 13, 75 cents. 301/461-1944.

COLONIAL FARM -- Wednesday through Sunday, 10 to 4:30, Claude Moore Colonial Farm at Turkey Run, 6310 Old Georgetown Pike, McLean. Take a self-guided tour of farm life for a low-income family in Colonial Virginia. Ongoing demonstrations of agricultural and domestic chores, such as spinning and candlemaking, will round out this history lesson. Adults $1; children under 12, 50 cents. 703/442-7557.

CHILDREN'S STORY HOUR -- Friday, 4:30 to 5:30, Potomac Overlook Park Nature Center, 2845 Marcey Rd., off Military Road, Arlington. Naturalists tell stories for pre- schoolers and kindergarteners. 528-5406.

SOUND OF MUSIC -- Friday-Saturday, 8 p.m.; Sunday matinee, 2:30, Vienna Community Center, 120 Cherry St. SE, Vienna (take the Beltway to the Vienna and Route 123 exit, take 123 to left on Park Street; Vienna Center is on the corner of Park and Cherry streets). A production of "The Sound of Music" geared for children and adults. Adults $6 in advance, $7 at door; seniors and kids under 12, $5 in advance, $6 at door. 938-8000, ext. 277.

CHILDREN'S RADIO THEATER -- Saturday, 8 a.m., WPFW 89.3 FM. "Gems for Judy," a story about two sisters who uncover the mystery of hidden jewels; "The Life of Rotten Garbage" a story about the fate of three vegetables on a grocery store shelf. Listeners can participate in a call-in following each program by dialing 783-3104.

SATURDAY MORNING AT THE NATIONAL -- Saturday, 9:30 and 11, Helen Hayes Gallery, National Theater. Canadian recording artists Chris and Ken Whitely keep the kids laughing, clapping and stomping to folk songs. Reservations recommended. Call 783-3372, 24 hours a day.

FOLK FESTIVAL -- Saturday 10 to 5, Sunday noon to 5, Rose Hill Children's Museum north of Frederick, Md. Take U.S. 15 north to Exit 8 to Motter Avenue; follow Motter to left onto 14th Street and left onto North Market Street, follow signs to Rose Hill. Demonstrations of colonial crafts and blacksmithing, children'srograms, hayrides and more. Adults $1; under 17, free. 301/694- 1646.

PUPPET SHOW -- Saturday, 11, The Cheshire Cat Bookstore, 5512 Connecticut Ave. NW. Puppeteer Tricia Brummer performs stories and songs for children age three and up. 244-3956.

TROLLEY MUSEUM -- Saturday and Sunday, noon to 5, Northwest Branch Regional Park, Bonifant Road between Layhill Road and New Hampshire Avenue, north of Wheaton. Sunday, 3, "Cinderella." The Montgomery Ballet Company performs excerpts of this well-known fairy tale; no admission charge but it's recommended you bring blankets or folding chairs for lawn seating. Trolley rides: $1 adults; under 18, 75 cents; under two free.

DAY ON THE MALL -- Saturday, noon to 3, Washington Monument Grounds, Sylvan Theater, The Mall. "A Day on the Mall for Special People," a program for handicapped children, features music, games, clowns, animals, balloons, a magician, refreshments and much more. 392-2836 or 737-1776.

STORYTELLING -- Saturday, 12:30 p.m., National Museum of African Art, 318 A St. NE, "Storytelling: Igbo Folktales." Experienced storytellers recount lore and history of the Igbo people of southeastern Nigeria. 357-2700.

CHILDREN'S PLANETARIUM -- Saturday and Sunday, 1 and 4, Rock Creek Nature Center, 5200 Glover Rd. NW. First show for children four to seven (must be accompanied by an adult); second show for ages seven and up. No latecomers are admitted. 426-6829.

ADVENTURE THEATER -- Saturday and Sunday, 1:30 and 3:30, Adventure Theater, Glen Echo Park, Glen Echo. "The Magic Flute," a one-hour marionette version of Mozart's opera in English, featuring dragons, flying horses and enchanters. $4, group rates available. Telephone reservations can be made by calling 320-5331 weekdays and performance days from 10 to 2.

KINDERFEST -- Sunday, noon to 5, Watkins Regional Park, 301 Watkins Park Drive, Upper Marlboro, Md. (take Beltway to Landover Road Exit, Rte. 202 south, to Rte. 214 east; make right at third light; park entrance is 1/2-mile on the right). "Fifth Annual Kinderfest." A day of family activities including carnival games, clowns, magicians, miniature train and carousel rides, petting zoo and more; nominal charge for refreshments, rides and booths. 249-9220.

BLUE SKY PUPPETS -- Sunday, 2, Rock Creek Nature Center, 5200 Glover Rd. NW, "Lights Out on the Bunny Brothers." A 45- minute presentation featuring singalong, music, puppet show and other entertainment relying on audience participation. 426-6829.