Ice cubes tinkled in glasses, a jazz musician talked music with an arts administrator, officials from two rival federal agencies grinned in conversation, and congressmen who normally grill both groups on their budgets took them aside and told funny stories.

The perfect mid spring party transpired last night, but the host, the immaculately black-suited pianist, Van Cliburn, was beside himself. While his guests strolled into the small lobby outside the Dumbarton Room of the Four Seasons Hotel and out onto a patio, Cliburn was a frenzy of activity -- spinning left, then right, searching above heads for whatever guest had to be introduced to whom.

He greeted his fellow National Council on the Arts member, Rosalyn open arms. He swept National Endowment for the Arts chairman Livingston Biddle and his wife Catharina over to see his mother, Rildia Bee Cliburn. He implored theater producer Harold Prince -- yet another National Council on the Arts member -- not to rush off to catch his shuttle to New York so soon.

Van Cliburn, the consummate pianist, whose onstage performances have worked his audiences up into a frenzy rivaled only by the performances of Luciano Pavarotti, had become the consummate host.

The occasion was his next-to-last appearance as a member of the National Council on the Arts, here in Washington for their quarterly meeting. His eight-year term is up. "Well, I wanted to have a little farewell," he said smiling.

"I've always wanted to meet you," said Rep. Sidney Yates (D-Ill.) to Cliburn, "ever since you won the Tchaikovsky Competition."

"That helped me along," said Cliburn politely about the competition which he won in 1958 in Moscow, skyrocketing him to fame at the age of 23.

Sen. Harold Johnson, from Cliburn's home town in Louisana and Cliburn launched into a discussion of the virtues of eating before a "performance" or after. ("If I have a bill anything before I perform," said Cliburn, patting his sides.)

"I had a great early career as a Van Cliburn look-alike," said a grinning National Gallery of Art director J. Carter Brown, who shares Cliburn's fair skin, blue eyes and light hair. "He had just won the Tchaikovsky Competition when I was in Moscow studying. We were both young, and in Moscow he was the only American of my age that they knew. They would not be disabused of the notion that I wasn't him. They would thrust pieces of paper at me yelling 'Van Cliburn! Van Cliburn!' So I had nothing to do but sign his autograph."

Cliburn, 45, has been on sabbatical from the concert hall since Sept. 30, 1978. "Twenty-four years of 60 to 100 concerts a year is a killing schedule," said Franklin Minor, his manager last night.

As he bobbed up and down in his chair looking for an expected late guest, Cliburn said he did not know when he would return. "I've been thinking about it," he said, smiling. "I haven't made up my mind yet.

"Oh, I'd like to come back. I hope somebody will want to hear me."

But he evaded the question of when and calmly denied that his career is on a downhill course. "One's career never stands still," he said, "in whatever you do -- in any creativity."

His days are filled, he says, with seeing friends and seeing the shows they are in -- like Renata Scotto in the Metropolitan Opera's "Manon Lescant," "To be able to be free, to know you can plan to do things, is wonderful."

He can barely remember the last time he recorded. "I guess it was two or three years ago."

There are some pieces of music he has recorded for albums -- on RCA -- but has never gone back to finish. He laughed about those almost in embarrassment.

"I will hear those -- one of these days. They have been there a long time," he said. "I had other things to do."