Would you believe Joan Baez, of all people, singing a torchy version of the ballad "Cry Me a River" as a jazzy saxophone vamps in the background? How about Baez dancing frenetically on stage as her band plays a disco instrumental modeled after "Kung Fu Fighting" Or Baez rocking away on a version of Rod Stewart's hit single "Sailing?"

To both their surprise and delight, that's what a nearly full house got Saturday night when Baez played at Georgetown University's sweaty, echofilled McDonough Arena. They also got imitations of Jimmy Carter, Bob Dylan, Henry Kissinger, Lily Tomlin and Sylvester Stallone from an energetic and high spirited Baez, who performed for more than 2 1/2 hours.

What may have made it easy for the crowd to accept Baez's new manner and repertoire was her opening allacoustic set, devoted to what she called the "memorabilia." The solo portion of her show included many of the songs she's been doing for years: Dylan's "Love Is Just a Four Letter Word," for instance, and The Band's "The Night They Drove Old Dixie Down."

But it was the new material, performed with the help of a five-piece electric band, that provided the evening's most riveting moments. Beginning with a reading of Traffic's "Many a Mile To Freedom" in which guitarist Elliott Randall and pianist Pat Rebillot were especially strong, the second half of the show seemed to prove that Baez is in some ways "younger" than she was a decade ago.

That's not to say she's abandoned either her activist stance or her somewhat sarcastic sense of humor. She dedicated "Joe Hill" to the late Julius Hobson and delivered a pointed jab to a well-known news magazine with an original called "Time Rag," but the self-righteous streak that has sometimes marred her work in the past was absent. It made for a balanced and quite enjoyable evening of music.