For a quick scan of all the places you may want to visit in Manhattan, start with the CULTURE BUS LOOP TOUR offered by the New York City Transit Authority: "See New York on $2.50 a day." The tour runs on Saturday, Sunday and most holidays from 10 to 6. It covers midtown and uptown -- including such Big Apple favorites as the Empire State Building and Central Park. For trip information, call 212/330-1234.

After being closed for over three months for restoration, THE DAIRY, the visitor information and exhibition center for Central Park is reopening this weekend with a photography exhibition and a walking tour of the Park, Sunday at 2. It's free, on the Park at 65th Street.

The CENTRAL PARK FOLKDANCERS will give a free performance on Sunday at 2 at the King Jagiello Statue, on 80th Street west of the Metropolitan Museum of Art. Call 212/673-3930.

The Metropolitan Museum of Art's Junior Museum at Fifth Avenue and 81st Street offers an EGYPTIAN STUDIO WORKSHOP Saturday at 1:30 and 3:30. Children ages five to 12 will use plaster, bandage and sculpture to learn to wrap mummies the way the ancient Egyptians did. Materials fee is $1.50. Free Egyptian films, gallery hunts and talks will also be featured Saturday and Sunday from 11 to 3:30. Hours: Friday and Saturday, 10 to 4:45; Sunday, 11 to 4:45; Tuesday, 10 to 8:45; Wednesday and Thursday, 10 to 4:45. Call 212/879-5500, ext. 3932.

For a change of taste, visit SCHAPIRO'S WINERY, which claims it's "the only functioning winery in Manhattan," at 126 Rivington Street. Free wine cellar tours and tastings are conducted every hour on Sundays from 10 to 6. Call 212/674-4404.

If you like festivals and flea markets, the LEXINGTON AVENUE FESTIVAL featuring continuous country and western music, rides, arts and crafts and ethnic foods will be held from 11 to 6 on Sunday, on Lexington Avenue, between 23rd and 34th Streets. Free. Call 212/674-5094.

The ANNEX ANTIQUES FAIR & FLEA MARKET on Sixth Avenue between 25th and 26th Streets includes over a hundred dealers of unique collectibles and objets d'art. Sunday, 10 to 6. Admission, 75 cents. Call 212/243- 5343.

Walter's World Famous LE FLEA MARKET features nostalgia and art deco as well as antiques and collectibles. That's Friday to Sunday from noon to 8 at 252 Bleecker Street in Greenwich Village. Call 212/255- 0175.

For film buffs, the 1981 MARGARET MEAD FILM FESTIVAL takes place Saturday and Sunday at the American Museum of Natural History. That's 41 anthropological and archeological films, 19 of them premieres. At 79th and Central Park West from 11 to 5. Suggested donation, $2.50, includes admission to Museum and films. Call 212/873- 1070.

If you haven't caught baseball fever, there is an IVY LEAGUE FOOTBALL GAME at Columbia's Baker Field on Saturday at 1:30. The Columbia Lions host the Yale Bulldogs. Reserved seats, $6 for adults, $3 for under 17. General admission, $3 adults, $1.50 under 17, at 218th Street and Broadway. Call 212/280-2546.

Opera fans can catch THREE OPERA CLASSICS in Manhattan this weekend at the Metropolitan Opera House, 64th Street and Broadway. On Friday at 8, there's "La Traviata," with Catherine Malfitano, Giuliano Ciannella and Renato Bruson (partial- view seats only, at $6 to $25). On Saturday at 1:30, it's "Die Frau Ohne Schatten," with Birgit Nilsson, Eva Marton, Mignon Dunn, Franz Ferdinand Nentwig and Gerd Brenneis (standing room only, at $5 and $6). Then, Saturday at 8, "Madame Butterfly," with Gilda Cruz-Romo, Ariel Bybee, John Alexander and Ryan Edwards (at $30, $35 and $55). Call 212/580-9830.

If you can't leave work earl there who can't seem to break away from D.C., the K-B Janus theater has a revival of Martin Scorsese's 1976 musical drama "NEW YORK, NEW YORK," starring Robert DeNiro and Liza Minnelli. Showtimes, Friday and Saturday: 1:15, 4:15, 7:10, 10:10. Sunday to Thursday: 1:15, 4:15, 8, at 1660 Connecticut Avenue NW. Call 232-8900.

For free information regarding what tickets may be obtained for theater, dance and concerts call 212/880-0755, Monday to Friday, noon to 6.