Comes the fall, and down drop the bazaars, festivals, fleas and flings. They're all over the place this weekend:

In WASHINGTON, the ST. GEORGE EASTERN ORTHODOX CHURCH 10th annual bazaar is Saturday 10 to 8 and Sunday 1 to 6 at the Church Hall at 16th and Webster NW. Middle Eastern dancers entertain, a sidewalk cafe sells ethnic foods, and there's a rummage sale. Free admission. ARMENIAN HOLY CROSS CHURCH BAZAAR is under the big tent at St. Luke's Methodist Church, Wisconsin Avenue at Calvert NW in Georgetown. Pastries, crafts and ethnic food, free admission 10 to 10 Friday and Saturday.

The Waterside Towers Residents Association OKTOBERFEST SOUTHWEST is Saturday in the Arena Stage parking lot, Sixth and M streets SW. Free admission noon to 5 to the yard sale with arts and crafts and German music. A BIZARRE BAZAAR is Saturday 11 to 5 by the Columbia Plaza Tenants Association; between Virginia and E Streets NW off 23rd, there'll be used items from books to records and chinaware. Free admission.

In MARYLAND, meanwhile, as is traditional, the last Sunday in September is time for the WASHINGTON SAENGERBUND OKTOBERFEST at the grounds of the German Orphan Home in Upper Marlboro. German music, food, beer, dancing and gemutlichkeit Sunday noon to dark; admission is $2 (under 16 free). Take exit 11-A south from the Beltway, through three lights then left on Woodyard Road. Call 301/585-7383.

The SIXTH ANNUAL POLISH BAZAAR AND FOLK FESTIVAL at White Oak Armory is sponsored by the Polish Catholic Pastoral Mission. Polish food, arts and crafts, music and dance Sunday 1 to 5. Free admission.

The BATTLE CREEK CYPRESS SWAMP SANCTUARY celebrates its second year with guided tours of the swamp, natural crafts, a "Wild Edible Sampler" table and more. Free Sunday 1 to 5. Take the Beltway to Maryland Route 4 east and two miles south of the town of Prince Frederick, turn right on Maryland Route 506. Take the first left (Gray's Road) to the entrance. Call 301/535-5327.

The FALL GREEK VILLAGE FESTIVAL is Friday, Saturday and Sunday, noon to 9 at the Greek Orthodox Church of Saint George, 7701 Bradley Boulevard (just off Seven Locks Road). Greek specialties from food to traditional music and dancing; admission is free, as is parking. Rain or shine.

OLD TOWN GAITHERSBURG FESTIVAL is Sunday 11 to 4 when the downtown area is blocked off from the Post Office to the City Police Station for music, a flea market, an antique car show, hayrides and carnival rides. Free. Raindate: Sunday.

Pieces of costumes make up the COSTUME LOFT RUMMAGE SALE by the Adventure Theater Rehearsal Hall in Glen Echo Park. That's free this Sunday noon to 4; take the Glen Echo exit from the Beltway and follow signs.

The fall ANTIQUES ARMS, MILITARIA, JAPANESE SWORD AND COLLECTIBLES show and sale is at the Greenbelt, Maryland, National Guard Armory Saturday and Sunday 9 to 4. Admission is $2 to see scarce and unusual items. Call 262-5735.

In VIRGINIA, the 13th annual HISTORIC OLD OCCOQUAN CRAFT SHOW is Saturday 10 to 6 and Sunday noon to 6. Free admission to see the works of 200 craftspeople from 14 states, plus live music mid-afternoon. Nine miles south of the Beltway via I-95, take the Occoquan exit (Route 123) 11/2 miles west to parking; shuttle buses are free.

It's an OLD-FASHIONED ICE-CREAM SOCIAL Sunday, with music by the Arlington Symphony, 2 to 5, at the Hyatt Regency Crystal City. Admission is $2 for ice cream and music by the symphony, in its 38th season. At 2799 Jefferson Davis Highway, Arlington.

The ITALIAN ARTS AND CRAFTS FESTIVAL at the McLean Community Center features arts and crafts as well as regional flags and cultural exhibits, music and food of Italy. Saturday 10 to 5 and Sunday noon to 5. Free admission at 1236 Ingelside Avenue. Call 790-9249.

LANGLEY SHOPPING CENTER'S OKTOBERFEST is Saturday 10 to 7 with a sidewalk sale, German band and food and beer for sale to benefit Children's hospital. Admission free at Chain Bridge Road between Old Dominion and Virginia Route 123. Call 734-0044.

An ANTIQUIES SHOW at Fort Ward Park (4301 West Braddock Road in Alexandria) is Sunday 10 to 5; food and entertainment, featuring bluegrass and jazz and 20 dealers showing and selling the old stuff. Free.