Sculptor Gaston Lachaise was hardly appreciated during his lifetime, but then he was a personal, idiosyncratic artist who didn't exactly change American art history. Still, his impressive nudes are worth seeing in "Gaston Lachaise: Portrait Sculpture," at the National Portrait Gallery through Feb. 15. CLASSICAL MUSIC

The Christmas music season is upon us with a predominantly Baroque flavor. Besides "Messiahs," which will be happening everywhere, two Christmas programs in Georgetown will feature less often heard Baroque music. Saturday night, in Gaston Hall at Georgetown University, Hesperus and Vocal Offering will present "A Star in the East," featuring music of Heinrich Schu tz and his contemporaries. At Dumbarton Avenue Methodist Church, Friday and Saturday, Linn Barnes and Alison Hampton will perform music of Vivaldi and others for two lutes -- a program that is becoming a Christmas tradition. The Christmas Revels, also becoming a tradition in Washington, will be celebrated Friday through Sunday at Lisner Auditorium.

One of the week's notable "Messiah" performances, to be presented by the Catholic University Chorus Friday night in the crypt of the National Shrine, will share the program with the world premiere of "In the Fullness of Time: Epistle and Hymn," a work composed by Leo Nestor to mark the 20th anniversary of the Second Vatican Council. The other large-scale staple of Christmas music, Humperdinck's "Hansel and Gretel," is available in at least two productions: by the Prince George's Civic Opera,Friday through Sunday at Bowie State College, and by the Fairfax Symphony Orchestra, Saturday (with a repeat Dec. 14) at Fairfax High School.; Rudolf Serkin's recital this afternoon at the Kennedy Center; Dame Joan Sutherland in a concert version of "Anna Bolena," Friday night at the Kennedy Center; the Boston Symphony, Saturday afternoon at the Kennedy Center; the King's Singers with the National Symphony, Thursday and Saturday nights at the Kennedy Center; the 20th Century Consort, Saturday night at the Hirshhorn; the Montgomery Chamber Orchestra, Saturday night at the National Bureau of Standards; flutist Gary Schocker, Saturday night at the Jewish Community Center; the Cleveland Quartet, Saturday night at the University of Maryland.

Finally, Gian Carlo Menotti's "A Bride From Pluto," an opera for children that had its world premiere a few years ago at the Kennedy Center, will be brought back by the Opera Theatre of Northern Virginia, Saturday night in the Thomas Jefferson Auditorium in Arlington. DANCE

The Paul Taylor Dance Company presents two programs containing three Washington premieres in matinee and evening performances today at the Kennedy Center Opera House. Maurice Hines' new dance musical "Uptown . . . It's Hot!" continues its run at the Warner Theatre. The George Mason University Dance Company program at the Harris Theatre Thursday through Saturday features the third part of "Freedom of Information," by guest choreographer Arnie Zane, along with other repertory. The premiere of a work by associate artistic director Anne Warren, plus choreography by Larry Warren, Murray Louis and Becci Parsons, constitutes the Maryland Dance Theater's 15th-anniversary program at the Prince George's Publick Playhouse Friday and Saturday. The Model Secondary School for the Deaf Fall Dance Concert features guest works by five professional choreographers, ranging in style from jazz to modern ballet, breakdance, ballroom and jazz tap, at Gallaudet College Friday and Saturday. The Glen Echo Dance Theater Annual Faculty Concert, Saturday and Sunday at the Glen Echo Park Studio, will feature the premiere of Pola Nirenska's "Trapped," to music by Philip Glass, along with other new works. FILM

Tomorrow at the Library of Congress' Mary Pickford Theater, David Lean's "Great Expectations," based on the Charles Dickens classic. Perfect family fare. At 7:30 p.m. Free.

The Truffaut Festival continues at the Biograph. Check daily listings for details.

Among current releases, "Shoah," Claude Lanzmann's incomparably powerful documentary on the Holocaust, playing in separate halves each day at the Key Theatre. Also Philip Borsos' Capra-esque "One Magic Christmas." POP MUSIC George Winston's pastoral piano is the essence of New Age music -- serene, introspective and quietly inventive. He's at the Kennedy Center Concert Hall tonight.

Todd Rundgren, precocious popster, recorded his latest album just by using his voice. When he plays at the Bayou tonight, he'll bring some tapes, as well as a live band.

Fans may be wondering who's playing behind the peripatetic Roger Daltrey at Constitution Hall on Wednesday. It's not the Who, but early reports indicate it's not bad.

Tony Bennett heads up a fine jazz and popular song program at the Patriot Center on Thursday (the hall is scaled down to 4,000 seats). Also appearing: Rosemary Clooney and Artie Shaw with his band.

This year's Christmas Revels are built around the Kentucky mountain yuletide experiences of Jean Ritchie, who popularized the lap dulcimer in the '50s. This always entrancing production will be held at Lisner Auditorium Friday, Saturday and Sunday.

In the past few years, the hammered dulcimer has become the rage in folk circles, and on Saturday, five of the best players share the stage at Georgetown University's Gaston Hall: Paul Van Arsdale, Walt Michael, John McCutcheon, Malcolm Dalglish (with Metamora) and Paul Reisler (with Trapezoid).

The closest he's coming is the Baltimore Civic Center on Saturday, but it may be worth the trip to catch John Cougar Mellencamp, who has evolved into much more than a midwestern Springsteen. THEATER

It's a week for actresses. In "A Walk Out of Water" (at the Studio Theatre), 81-year-old Katherine Squire gives a wonderfully crusty performance as a blind grandmother, easing her dreamy granddaughter over the hurdles of adolescence. Playwright Lillian Hellman is vividly portrayed by Zoe Caldwell in the one-woman show "Lillian" (at the Kennedy Center Terrace Theater). Meanwhile, Halo Wines continues her wrenching portrayal of a young woman who has lost the will to live in "'night, Mother" (at Arena's Kreeger Theater).