Okay, so maybe you don't want to spend Christmas reading the newspaper. But before you add this section to the pile of torn-open gift wrappings to fuel your Yule flames, think ahead. When the stockings are unhung, the toys played with, the goose cooked and eaten, what? When all the Merry Christmases are said and done with, and the flames on the plum pudding have flickered out, what then? Maybe you'll want to get out of the house, away from the mess and the dirty dishes and that logy feeling in your stomach. We're here to help, with some suggestions. You could hop into your jogging shoes or your car and head for the Ellipse to admire THE NATIONAL CHRISTMAS TREE, a 30-foot blue spruce. While you're there, say thanks to Donder and Blitzen and Rudolf and the gang who are resting on the Ellipse while on leave from Santa's team and the National Zoo. And visit THE NATIVITY SCENE, an outdoor creche with live animals. At the east end of the Mall, there's a 50- FOOT WHITE SPRUCE glittering on the grounds of the Capitol. To warm up, duck into the lobby of the Hyatt Regency Hotel at 400 New Jersey Avenue NW for a gander at a GINGERBREAD VILLAGE of six sugar-trimmed buildings and a 12-foot church. Washington's real churches are all decked out for Christmas, too. THE MORMON TEMPLE in Kensington is aglow with 50,000 tiny white lights. The NATIONAL SHRINE of the Immaculate Conception has a life-size creche. And the NATIONAL CATHEDRAL is adorned with swags of poinsettias, Christmas trees hung with poinsettia blooms and an old-fashioned children's Christmas tree decorated with popcorn and cranberry garlands and gingerbread people. If this inspires you to burst into song, stick around for the CAROL SING at 4. If you prefer skating to singing, the outdoor ICE-SKATING RINKS on the Mall and at Pershing Park (Pennsylvania Avenue between 14th and 15th Streets NW) will both be open on Christmas afternoon, with skate rentals available. Now that we've gotten you through Christmas Day, what are you going to do over the weekend and all the next week? Eventually you'll have to face the melancholy chores of taking down the Christmas tree and paying the Christmas bills, but not yet. And don't join the crass crowd that takes presents back to the stores the day after Christmas. Instead, head for the Museum of American History to sample holiday customs from all over or to the Kennedy Center to sample free holiday entertainment. At the Museum of American History, there will be ROVING SINGERS every day through Thursday, December 31, and a jovial JUGGLER will keep things in the air every day between 12:30 and 3:30 in the Physical Sciences section on the first floor. The original 1933 movie of LITTLE WOMEN, featuring Katharine Hepburn, will be screened daily at 10:30 am in Carmichael Auditorium, and demonstrations of CLOCKMAKING AND HOURGLASS BLOWING will take place every day from noon to 4 in the Timekeeping Exhibit on the first floor. In the Nation of Nations area on the second floor, there will be demonstrations of DREIDEL-MAKING and Jewish paper cutting, menorah making and Victorian holiday decorations, also noon to 4. At the same time on the third floor, you can watch instrument making and 19th-century printing. And in the computing area on the first floor daily from noon to 4 you can try your hand at such GAMES as whist, cribbage, hearts, backgammon, checkers, dominoes and dreidel-spinning. While you're there, check out the VICTORIAN DOLLHOUSE on the second floor and the White House dollhouse in the First Ladies' Hall; they're both decked out for Christmas. A dozen r listen to seasonal sounds. The Folk and Baroque Players begin at noon with JEWISH INSTRUMENTAL MUSIC, and the National Capitol Area Salvation Army Band, the Philadelphia Mummers Association Aqua String Band and the Spiritual Echoes follow. On the second floor, in the Nation of Nations ares, the Deal Junior High Swing Choir sings at noon and on the third floor at 2, the Over the Hill Gang will play homemade instruments. At 1:30 and 3, Scrooge gets the Christmas spirit in a performance of Dickens' A CHRISTMAS CAROL in Carmichael Auditorium. And just outside the cafeteria, you'll be able to sample Bulgarian banitza and baklava and German marzipan pigs, mushrooms and chimney sweeps. On Sunday the Rochelle Helzner Quartet starts the music around the pendulum program with JEWISH FOLK SONGS at noon, followed by the Zemer Chai, the Takoma Mandoleers and the Ralph Herndon Singers. A Christmas Carol plays again in Carmichael Auditorium at 1:30 and 3, and there will be tastings of Bulgarian banitza and baklava and German marzipan pigs, mushrooms and chimney sweeps from noon to 4 outside the cafeteria. The Marlton Elementary School Chorus will sing on the second floor at 2 and 3, and Gene Ashton plays homemade instruments on the third floor at 2. On Monday you can watch a LUTE AND GUITAR DEMONSTRATION on the third floor at 11. The St. Columba Handbell Ringers start things off at the pendulum at noon, followed by the Fabrangen Fiddlers, the Durning String Band and Rumisonko, from Latin America. The Adas Israel Youth Choir sings at noon and 1 on the second floor, followed by the Kingman Elementary School Glee Club at 2 and 3. And it's your last chance to catch A Christmas Carol in Carmichael Auditorium at 1:30 and 3. You can munch on Greek basilopita and German marzipan outside the cafeteria from noon to 4, and listen to a Philadelphia Mummers STRING CONCERT near the gunboat Philadelphia on the third floor at noon and 3:30. And the Over the Hill Gang gives a family concert at 2 in the musical instruments area on the third floor. Tuesday, at 11, Mary Price demonstrates BOWED STRING INSTRUMENTS on the third floor. At noon, gather around the pendulum to ring in the afternoon with the Lawton Memorial Handbell Choir. Stick around for Jewish folk music, a women's chamber consort and some German folk songs. The Junior Choir of Chevy Chase Presbyterian Church sings at noon and 1 on the second floor, followed by the Gaywood Elementary School Children's Choir. A workshop on the everyday LIFE OF A SOLDIER -- with emphasis on Christmas at Valley Forge during the Revolution -- will be given in the Discovery Corner at noon. Bulgarian banitza and baklava and Greek basilopita will be served outside the cafeteria from noon to four and in Carmichael Auditorium at 1:30 at 3, you can watch the court trial from Dickens' The Pickwick Papers. Bruce Hutton plays manufactured and homemade instruments on the third floor at 2. On Wednesday there's a demonstration of FOLK INSTRUMENTS on the third floor at 11. Music around the pendulum starts at noon with Irish songs and harp music, followed by Jewish folk music, Bob Devlin's One-Man Band and the Potomac Ringers. There's a Hebrew singalong on the second floor at noon and 1, followed by performances of the children from the Bethesda Academy of Performing Arts at 2 and 3. In the Discovery Corner at noon, you can learn what it was like that Christmas at Valley Forge. Banitza, baklava and basilopita will again be available outside the cafeteria and you can catch the court scene from The Pickwick Papers in Carmichael Auditorium at Station Elementary School Chorus sings on the second floor at noon and 1, followed by the CHILDREN'S CHORUS of the Church of Jesus Christ and the Latter Day Saints. The life of a Revolutionary War soldier wintering at Valley Forge will be depicted in the Discovery Corner at noon. It's your last chance to sample banitza and baklava outside the cafeteria from noon to four and to catch The Pickwick Papers in Carmichael Auditorium at 1:30 and 3. And a FAMILY CONCERT including homemade instruments takes place on the third floor at 2. All events in the Smithsonian's holiday celebration are free, with no tickets required. The Kennedy Center's Holiday Festival, a Christmas present of mainly free events in the Grand Foyer, continues through Thursday. This Saturday, at 10 and noon, the Patowmack Ancients FIFE AND DRUM CORPS marches and plays, while Babes the Clown mimes from 10:30 to 1. The Potomac English Handbell Ringers perform at 1:30 and 4, followed by the Prince Georges Choral Society at 7. In the Theater Lab at 11, noon and 1, the Sonshine Puppet Company presents THE FACES OF CHRISTMAS. Tickets have already been distributed, but empty seats will be filled 15 minutes before each show. Tickets to hear the New York String Orchestra in the Concert Hall at 7:30 are $5, available at the Concert Hall box office. Free events on Sunday include the Jubilee CHORAL FESTIVAL at noon, the Prince Georges Barbershop Singers at 1, the Iona Bells at 3:30, the Ligon Chamber Singers at 6 and the Keren Ohr Israeli Dance Troupe at 7. At 8 in the Concert Hall, there's a HANUKAH FESTIVAL program, including a menorah lighting and a sing-along. Tickets, at $6, are available at the Concert Hall box office. On Monday at 11 Bob Devlin's ONE-MAN BAND starts off the free events in the Grand Foyer, followed by the Montage Wind Quintet at noon, Craig Babcock's mimes at 1, the St.Columba Handbell Ringers at 2, and Musica Concordia at 6:30 and 8. The 12th-century Play of St. Nicholas, a MUSICAL DRAMA, starts at 8:30 in the Concert Hall, with all tickets $7.50. On Tuesday, December 29, Terry and Linda's PUPPET COMPANY performs in the Grand Foyer at 11, 1 and 2:30, followed by the Woodbridge Community Singers at 3 and the Pan-Orthodox Singers at 6:30 and 8. Free tickets for the Children's Works production of WE LIVE IN THE CITY have already been distributed, but empty seats will be filled 15 minutes before the 11:30 and 1:30 performances in the Theater Lab. And the Play of St. Nicholas runs again in the Concert Hall at 8:30, with all seats reserved at $7.50. On Wednesday, Bob Devlin's One-Man Band leads off the free events at 11am, followed by the MIMING of Craig Babcock at 1, Israeli folk dances by the Kinor Dance Company at 2, the D.C. Youth Chorale at 3 and the Thomas Circle Singers at 6:30. Tickets to the FAIRFAX SYMPHONY Orchestra performance in the Concert Hall at 8:30 are $8.50 End the year nicely with Joe Nicely, A JUGGLER, on December 31 at 11 and noon in the Grand Foyer. He'll be followed by mime Craig Babcock at 1 and the Alexandria Community Singers at 7. The grande finale to the Holiday Festival is A NIGHT IN OLD VIENNA, with music by Mozart, Schubert and Strauss played by Alexander Schneider and Friends. It starts at 9 in the Concert Hall and tickets, at $7.50, are available at the Concert Hall Box office. Afterward, at about 11, there will be DANCING in the Grand Foyer. Anyone holding a ticket stub to any December 31 Kennedy Center performance will be admitted. You can view the Christmas DECORATIONS AT THE WHITE HOUSE in free candlelight tours December 29 and HOUSE and Toy Museum Christmas exhibit, which includes a revolving musical tree, continues through December 31 at 5236 44th Street NW. Hours are 10 to 5 Tuesday through Saturday (except Christmas), noon to 5 Sunday, and admission is $2 for adults, $1 for children under 14. RETABLOS DEL PERU, an exhibit of Nativity and other religious scenes by Andean folk artists, is on display through January 17 at the Museum of Modern Art of Latin America, 201 18th Street NW. It's open Tuesday through Saturday, except Christmas, from 10 to 5 and admission is free. The POINSETTIAS are still blooming at the United States Botanic Garden Christmas show, through January 1. The garden, at First and Maryland Avenue SW, is open daily except Christmas from 9 to 5 and admission is free. Brookside Gardens, 1500 Glenallan Avenue in Wheaton, continues its poinsettia and greenery show through January. It's also free and open 9 to 5 except Christmas. SYMBOLS OF FAITH from Christianity, Judaism and Islam are on display at the National Geographic Society's Explorers Hall, open 9 to 6 weekdays (except Christmas), 9 to 5 Saturdays and 10 to 5 Sundays. You have until January 3 to catch THE NUTCRACKER, either the Washington Ballet production at Lisner Auditorium (call 362- 4644) or the American Ballet Theater version at the Kennedy Center (call 254-3600). A CHRISTMAS CAROL remains at Ford's Theater through January 3 (call 347-4833) and A BONZO CHRISTMAS CAROL plays through December 30 at D.C. Space (call 462-1073). The Elves and the Shoemaker, A PUPPET PRODUCTION, remains at the Smithsonian's Discovery Theater through January 3 (call 357-1500). When Christmas is over, KWANZAA, which is based on African harvest festivals, is just beginning. The Smithsonian's Museum of Natural History marks the opening of Kwanzaa Saturday at 8 with a free balaphone and kora concert. And Kwanzaa WORKSHOPS FOR CHILDREN will be held daily at 11, December 28 through 31, at the Museum of African Art, 316 A Street NE. Monday and Wednesday five- to seven-year-olds will make Maasai-style necklaces, and Tuesday and Thursday eight- to 13-year-olds will learn about the African art of applique and create their own stories on cloth. Advance reservations are necessary, so call 287-3490, ext. 41. Also at the Museum of African Art, Monday through Thursday at 2, there will be storytelling and games and songs, with emphasis on the Kwanzaa principle of the day. While kids soak up Kwanzaa, adults can watch THE SPORT OF KINGS at Laurel Race Course. First race starts Saturday at 12:30, and the horses run daily except Sunday at that hour through December 31. On closing day -- until spring -- you can not only try your luck at the betting windows but also enter a drawing for a vacation for two in Mexico. By this time you may be so tired of celebrating you'll want to think about spending New Year's Eve at home. If so, you can curl up in front of the television and watch MARX BROTHERS MOVIES on Channel 20 all day and part of the next. The fun starts at 1 with Copacabana, followed by Horse Feathers at 5:30, Duck Soup at 7, Monkey Business at 8:30, Love Happy at 10 and Coconuts at 11:30. Happy New Year.