The atrium of I.M. Pei's East Wing of the National Gallery has proven to be an altogether splendid space, but it has never looked as appealing as when enlivened by the vivid sprinkling of modern sculpture, part of an exhibition of 73 works selected from the collection of Patsy and Raymond Nasher of Dallas, now in the museum's public spaces. The exhibition is not encyclopedic, but it touches many 20th-century bases and the quality of the individual pieces is high. Most important, there's an electric charge between the sculptures and Pei's dynamic space.

CLASSICAL MUSIC Washingtonians will be able to attend three operas this week:

A single concert performance of Mussorgsky's "Boris Godunov" will be given tomorrow night at the Kennedy Center, with Mstislav Rostropovich conducting the National Symphony Orchestra, three choruses and an international star cast in preparation for taping for Erato Records.

The Summer Opera Theatre will open its season, tomorrow night at the Hartke Theatre, with Mozart's "The Magic Flute." There will be repeat performances on July 8, 10, 12 and 14.

The Wolf Trap Opera Company will open its summer season Friday evening with Rossini's "The Barber of Seville," to be repeated on July 12, 15 and 17 at the Barns.

There are also two piano festivals:

A series of lunch-hour recitals will begin Monday and continue through Friday at the World Bank, featuring Philip Hosford on Monday, Tzvetan Konstantinov Tuesday, Edward Newman Wednesday, Raymond Jackson Thursday and Francis Conlon Friday.

Preliminary rounds of the William Kapell piano competition will be held this week at the University of Maryland. The University's annual piano festival will begin its public concerts Saturday evening with the James Buswell-Leslie Parnas-Lee Luvisi Trio performing in the Tawes Theater and will feature recitals by internationally famous pianists every night next week.

Also worth noting: the Washington Camerata, Tuesday evening at the Washington Cathedral; the Annapolis Brass Quintet, Friday evening in the Baird Auditorium; the Georgetown Symphony Chamber Players, Saturday evening at First Baptist Church on 16th St. NW.

DANCE Stewart Carrera presents a solo program of Bharata Natyam, the classical dance of southern India, at American University's McDonald Recital Hall this afternoon.

"Tango Argentino," the hugely popular dance revue that originated in Paris and made its Washington debut at the Warner Theatre last year, returns for a two-week engagement, this time at the Kennedy Center Opera House, starting Wednesday evening.

Michelle Ava and David Appel, two area choreographers, share a program at Dance Place featuring their latest works, including solos and group pieces, Friday through Sunday nights.

FILM Starring Steve Martin and Daryl Hannah, "Roxanne" is the most unabashed and satisfying romantic movie in years. Working from Edmund Rostand's "Cyrano de Bergerac," Martin and director Fred Schepisi have created an intoxicating, swooningly comic love story about the glories of eccentricity, the triumph of peculiarity and one-of-a-kind-nesss. As C.D., the fire-chief hero, he moves with a dancer's graceful verve; he's the Baryshnikov of comedy.

POP MUSIC For all those aspiring songwriters, Tuesday looks to be a craftsman's night: Kris Kristofferson is at Wolf Trap, Loudon Wainwright at Blues Alley, Dwight Yoakam at the Warner and Chris Isaak at the 9:30 (he's also there on Wednesday).

The rhythms of Louisiana abound this week with File at the Birchmere on Wednesday, the Neville Brothers sharing the Merriweather Post Pavilion stage with Santana on Friday and Dewey Balfa's Cajun band at Twist and Shout, also on Friday.

Whitney Houston is back at the top of the charts; she's also at the Merriweather Post Pavilion on Saturday and Sunday.

THEATER Arthur Miller's "The Crucible" (at Arena Stage), a drama about the Salem witch hunts, was the playwright's response to McCarthyism of the 1950s. McCarthy has long since been discredited, but the play remains as potent as ever, especially as staged with incisive force by Zelda Fichandler and vigorously acted by the large Arena cast.

Also worth another look: "Ian McKellen Acting Shakespeare," now back in town at the Olney Theatre.

CAPTION:Daryl Hannah