It began as high camp and got higher as the evening progressed. What a gas! It was like an oversized three-ring circus.

There on the stage of Tawes Theater at the University of Maryland were 10 grand pianos -- not all the same size, but 10 grands all waiting to be massaged by anywhere from one to 30 pianists.

Not until near the end of the affair, when the prelude to Bizet's "Carmen" was played, did all 30 get to work at the same time. And they didn't play the whole work, just the opening Toreador Mach and Song. But what a sound!

Have you ever heard 30 pianists beating the ivories off 10 grand pianos? It's a unique experience, to say the least.

The whole idea, called "An Extravaganza for Multiple Pianos," was masterminded by Eugene List as a fund-raiser for the Piano Competition and Festival. The house was sold out. List was front-and-center amid all the din, acting as soloist in several juicy phantasmagorias by Gottschalk, like "The Union," which included "Yankee Doodle" and a softened-up version of "The Star-Spangled Banner." It is easy to appreciate List's generosity in contributing her services, as did the other 29, but it is not possible to forgive his making a mess of the exquisite Arensky Waltz and the Brazileira by Milhaud.

The piano power on the stage was awesome. There, buried in the assemble, was Bradford Gowen, last year's winner of the Kennedy Center's International Competition for Excellence in Playing American Music. There were four members of this week's competition jury; Thomas Mastroianni, head of Catholic University's music department; Haskell Small, Washington composer-pianist; and such distinguished professors of piano as Evelyn Swarthout Hayes and Nelita True, all crashing around the Overture to Rossini's "Semiramide." During the Gottschalk Grand Tarantella, who was sitting there turning pages but Harold Schonberg, for three decades the music critic of The New York Times. Yes, indeed, there was lots of class.

But not so much class in the music. For one thing, it turned out to be impossible to get 10 grand pianos all in tune at one time, and the longer the music went on, the more the pianos slipped in pitch. By intermission it was pretty ripe up there.

And another thing: It is very hard for pianists to keep both eyes on the music and still have an eye for a conductor. Every once in a while you could hear four or five different ideas about just when a downbeat was going to occur. But it didn't matter. Everyone was having a ball, and it was all for a good purpose.

By the time the terrific 30 got to the Hungarian Dance, the one Brahms wrote for "The Great Dictator," and after that, for a finale, "The Stars and Stripes Forever," the audience was ready to laugh and clap in rhythm.

P. S. The program said "William Tell" Overture, but all they played was the only part people ever want to hear of that piece anyway, the part that goes "Hi-yo, Silver, AWAY!"