How do you celebrate the 75th birthday of a musician with the kind of clout wielded by Sir Georg Solti? On PBS tonight (9 p.m., Channels 26 and 32 and Maryland Public Television), the Chicago Symphony Orchestra and a few thousand close friends mark the occasion with a number of unusual spectacles: Placido Domingo conducting, Sir Georg playing the piano and the world premiere of a composition by John Corigliano gradually solidifying into a neoimpressionist rearrangement of "Happy Birthday to You."

The occasion has no more spontaneity than any other performance by the Chicago Symphony under Solti's baton. But even at a birthday party, with inscribed balloons cascading from the ceiling and a whole audience standing to sing "Happy birthday, Sir George," spontaneity isn't everything.

The audience doesn't bother with the Hungarian pronunciation ("Gay-org") affected by some of the well-wishers who pop up for brief greetings during the hour-long celebration. To the ticket-buyers in Orchestra Hall, as to Joan Sutherland, Leonard Bernstein, Itzhak Perlman and Placido Domingo, he is "Sir George" or simply "George." Some well-wishers, torn between English and Hungarian, compromise with an Italian "Happy birthday, maestro."

By any name, he has been and remains a formidable musician. In his 18 years with the Chicago Symphony, Solti has made it the most exciting orchestra in the United States, possibly in the world. His recordings for the London/Decca label began to dazzle the world back at the dawn of the stereo era when he conducted the complete "Ring" cycle. Since then, he has won 26 Grammys -- more than any other musician -- including 18 with the Chicago Symphony. "I want to be always the best," he says during a brief interview shown on "Solti at 75: A Celebration!," and most of the world seems to think he has fulfilled that ambition.

The Chicago Symphony plays (as always) immaculately and powerfully during this rather miscellaneous program under three conductors: Domingo opening the evening with a crisply lyrical overture to "Die Fledermaus," assistant conductor Kenneth Jean in Corigliano's "Bells of Ravello" and Solti, with Domingo and Kiri Te Kanawa singing the love duet from Act 1 of Verdi's "Otello." Solti also conducts, from the keyboard, in Mozart's Concerto in E-flat for Two Pianos, K. 365, with Murray Perahia as his very able partner.

In its sheer diversity, as well as the quality of performance, this brief program gives a fair idea of what Solti's name stands for.