New York With the exception of "Sugar Babies," it was beginning to look as if the smash Broadway musical would be conspicuous by its absence this season. Last week changed all that. Musical comedy in the exuberant tradition sprang back to life with a whoop and a holler. First came "Barnum," a razzle-dazzle tribute to the great Phineas T. It was followed the very next night by "A Day in Hollywood/A Night in the Ukraine," a Broadway version of a British hit that proved, among other things, that long on title doesn't mean short on fun. "A Day in Hollywood/A Night in the Ukraine" animates the Golden Theater with a tribute to the golden age of Hollywood filmmaking. Designer Tony Walton's curtain provides the visual theme with its replica of the sidewalk outside Grauman's Chinese Theater. The handprints and footprints of the famous are imprints, not in the sands of time, but in commemorative concrete. The curtain rises to disclose a red-lacquered theater facade in front of which a sextet of entertainers recall and affectionately lampoon the pleasures -- particularly the musical pleasures -- ot talkies past. The players wear natty Michel Stuart ushers' uniforms. The songs by Dick Vosburgh and Frank Lazarus are intermingled with a whole pastiche of melodies by America's legendary tunesmiths. "A Day in Hollywood" also celebrates famous feet. While the performers sing their way down memory lane, Nikki Harris and Albert Stephenson, on a narrow catwalk above the entrance doors, give pedal impersonations of Charlie, Marlene, Judy, Mickey and Minnie, Fred and Ginger, to name a few. The two-level divertissement is as imaginative as it is droll. The production stylishly directed and choreographed by Tommy Tune brims over with delights and surprises. "I Love a Film Cliche" parodies Hollywood bromides , from gangster epics to jungle romances in a series of classic one-liners. "Doin' the Production Code" reveals more tap-dancing rhythms than were ever dreamed of in Will Hays's no- no philosophy. One of the show's happy inspirations is a reprise of Richard A. Whiting songs. And you have never appreciated the possibilities of "The Good Ship Lollipop" until you have heard it performed by a statuesque blonde (Peggy Hewett) on a baritone sax. "A Night in the Ukraine" is a one-act musical. According to the playbill, it is loosely based on "The Bear," by Anton Chekhov, identified in true Hollywood hyperbole as "Russia's greatest gag writer." Mr. Vosburgh has been inspired to imagine a Chekhovian joke in the Marx brothers manner. The results are hilarious, thanks to the travesty's Marxian dialogue and to the performances by David Garrison (Groucho-Samovar), Priscilla Lopez (Harpo-Gino), Mr. Lazarus (Chico-Carlo), and Miss Hewett (Mrs. Pavlenko) in the grand-dame Margaret Dumont manner. Wally Harper directs the felicitous two-piano accompaniment, abetted from time to time by Mr. Lazarus at the onstage keyboard. This "musical double feature" is a day and a night to remember. — A Day in Hollywood/A Night in the Ukraine; Musical double feature by Dick Vosburgh (book and lyrics) and Frank Lazarus (music). Directed and choreographed by Tommy Tune with Thommie Walsh as co-choreographer.