This past March, Gene Kelly hosted an "In Performance at the White House" broadcast showcasing three sterling examples of intrinsically American dancing. The last of these was a small contingent of dancers from the San Francisco Ballet who performed the "Ragtime" section of company co-director Michael Smuin's "Piano Pieces." Set to music by Igor Stravinsky, the dance ran the gamut from jazz to tap to the freewheeling moves of the Hollywood movie musical; the dancers, however, never lost the elegant, long-stemmed look of the classically trained performer.

The San Francisco Ballet excels in this sort of balancing act between pirouettes and pizzazz. This weekend at Wolf Trap the troupe, America's oldest, performs a wide variety of works -- abstract pieces, dances based on Shakespearean plays, the above- mentioned tap/jazz/show potpourri -- created exclusively by resident choreographers. The plot-oriented ballets include co- director Lew Christensen's "Pas de Six from Beauty and the Beast" and a duet from Smuin's interpretation of "Romeo and Juliet."

Just when you thought that Balanchine and company had done everything that could be done with Stravinsky, along comes a host of new works set to the master's scores by San Francisco's dancemakers. In addition to Smuin's "Piano Pieces," which consists of 13 stylistically varied miniballets, there's assistant director Robert Gladstein's "Symphony in Three Movements," a pure- movement ballet for 33 dancers that follows Stravinsky's pungent and complex score to the letter. Resident choreographer Val Caniparoli also employs a melange of the composer's music in his "Love Lies Bleeding," a segmented, contemporary ballet about plant life.

If there's one dancer who exemplifies the athletic good-humored San Francisco style, it's David McNaughton. This high-flying sprite, at home in both abstract and theatrical roles, will be moving east after this engagement to join the New York City Ballet. Catch his pyrotechnics before he ventures into new territory. THE SAN FRANCISCO BALLET -- At Wolf Trap Friday and Saturday at 8:30. Lawn $7, seat $14. FREE LECTURE -- There'll be free ballet lectures and demonstrations at 7 on Friday and Saturday next to the stage area.