ART FOR SHORE On the way to the beach this weekend, stop over at the 25th annual Annapolis Arts Festival for displays of photography, painting, pottery and other handiwork of more than a hundred artists. There'll be music, too, with the New York City Swing Band at 7 and 9:30 Friday, the Crests at 7 and 9:30 Saturday and the original Ink Spots at 6 Sunday. For kids 3 to 10, the Discovery Tent is full of participatory arts and music, but register as soon as you get to the festival because it fills up quickly. The festival is 11 to 11 Friday and Saturday and 11 to 8 Sunday at the city dock. Tickets are $4, $1 for under 12. 301/267-7922.

FABULOUS FATHERS Father's Day is Sunday, so why not treat Dad to the annual "Pops" concert (whoa) by the Washington Male Chorale at 5 Sunday at the Prince George's Publick Playhouse, 5445 Landover Rd. in Hyattsville. Tickets are $7.50, $5 for students and seniors. Call 277-1710 for information.

FAIRFAX FROLICS Old-fashion good times twist anew at the sixth annual Fairfax County Fair 10 to 6 Saturday and Sunday at George Mason University. Redskin quarterback Jay Schroeder will help to open the fair, which boasts nonstop entertainment by, among others, the Fairfax County Dance Company, Sugarfoot Cloggers, Star Witness playing top 40 and Grass Action with bluegrass. There'll also be a 10K race at 8 a.m. Saturday (register 6:30 to 7:30), history exhibits, hayrides and pony rides and the displays of 350 organizations covering everything from arts to pets to health to tourism. It's $2, under 12 $1. Call 691-FAIR.

NEW NOTES Through folk-pop-rock fusion, the New Song movement popular in Central and South America addresses political and social issues. The beat comes to town noon to dusk Saturday at the New Song Festival '87 in the courtyard of the Wilson Center, 15th and Irving NW. Musicians include the Haitian singer/guitarist Rameza, Native American chants by the Piscataway Singers, the Arab ensemble Al-Watan and the local foursome Lifeline. It's $5; food and crafts will be for sale. Call 483-5825.

POLITICAL PUNCHES Nothing is sacred when it comes to Washington's political satire community. Here's more proof:

Mild-mannered current or former Capitol Hill employees by day, political pranksters by night, the Capitol Steps do their stuff at the Herndon Community Center, 814 Ferndale Ave., at 8 Sunday. Your $15 benefits the Herndon Clubhouse Project, promise. Call 437-6750.

The Gross National Product hits d.c. space with the revue "A Man Without a Contra," all about you-know-who and you-know-what. It's at 443 Seventh St. NW; showtimes are 7:30 Friday, 7 and 8:30 Saturday; the show continues Wednesdays through Saturdays through July. Tickets are $8 during the week, $10 on the weekends. Call 347-1445.

HISTORIC MOMENTS Watch history pass you by at the Grand Militia Muster on the Governor's Field in St. Mary's City 10 to 5 Saturday and Sunday. A dozen groups of 17th-century reenactors will compete in pike, musket, sword and dagger, military drill, cooking and costume categories. Children can go back in time to play 17th-century games like ninepins, an early form of bowling. From the Beltway, take Rte. 4 to Solomons, cross the Thomas Johnson Bridge and follow the signs. Call 301/862-0990.

EUREKA! DISCOVERIES ON WESTERN PLAZA

What do a see-through refrigerator, an electric toilet-paper-roller and a space solar-energy conductor have in common? All are inventions of children, kindergarten to eighth grade and all, along with twoscore others, will be on exhibit at the U.S. Patent Model Foundation's Invent America! opening celebration 1 to 5 Sunday at Western Plaza, Pennsylvania Avenue between 13th and 14th NW. Beside the youthful exhibit, Dick Rutan and Jeana Yeager, copilots of the nonstop-round-the-world Voyager, will be on hand, as will the giant chompers from the movie "Jaws" and an exhibition of 19th-century patent models. If it rains, it's at the J.W. Marriott at 1331 Pennsylvania Ave. NW. Call 737-1836.

On Saturday at Western Plaza, the American Indian Summer Festival features Native American arts, dance, crafts and fry foods, including tacos and buffalo burgers, from 10 to 5. Admission is free. Call 343-3592 on Friday only.

FANCY ROPES Put all of life's worries into perspective at the 14th annual World Invitational Double-Dutch Championship, in which 300 kids from 31 states and Canada will twirl the double strands of jump ropes at George Washington University's Smith Center. They'll be competing in compulsory and speed jumps and freestyle routines 10 to 4 Saturday at 600 22nd St. NW. Tickets are $3.50, $1.50 under 12. Call 673-6920.

REST OF THE BEST The Gay Men's Chorus sings at 7 Friday and Saturday at the Departmental Auditorium on Constitution Avenue between 12th and 14th NW. Tickets are $10 to $20. 462-6969 . . . the annual Washington Storytelling Festival at Glen Echo Park is noon to 6 Saturday and Sunday. Free. 698-5456 . . . John Prine performs at Wolf Trap's Filene Center at 8:15 Friday with opening act the Seldom Scene. 432-0200 . . . The 450 dancers of the Feet First Jazz and Tap Dancers perform at the Sylvan Theater on the Washington Monument grounds at 1 and 4 Saturday. Free. 656-9076 . . . The Vince Lombardi 10K is 7:30 Sunday at Georgetown University. Registration ($15) is 6 to 7; spectating is free. 356-1178.