More than once, operetta has been declared a dead art form. Yet this ancestor of the American musical is undergoing a revival. Perhaps its dated allusions and saccharine harmonies are appealing--as safe targets--to our fin-de-siecle cynicism.

The In Series, on George Washington University's Mount Vernon campus, is running "Fabulous Frimlfest," a glittering revue of onetime hit songs from the operettas of Rudolf Friml, whose music captivated the American public from the pre-World War I era to the 1930s. It is clear from this production that the buoyant, jocular music of the Czech-born Friml is a thing apart from the musing nostalgia, melodious confections and pungent wit of the classic waltz-laden Viennese operetta.

The stellar cast on Friday evening included sopranos Mary Gresock, Millicent Scarlett and Melissa Unkel, tenors Reginald Bouknight and Bryce Westervelt, and baritones Lewis Preeman and James Hall. "Some Day" (from "The Vagabond King") gave us an enrapturing chance to hear Scarlett's radiant voice, while "Rose Marie" (from the operetta of that name) in duo form showed Westervelt and Hall's close partnership at its resonant best. Unkel's soprano has a lovely delicacy that was especially fine-tuned in her role as a flirtatious single.

Well-timed teamwork is the key to the production's success, with the singers' enlivening dialogue and comic asides linking the songs as they switched from duets reminiscent of Jeanette MacDonald and Nelson Eddy to the old-boys zeal of the barbershop quartet offerings, ragtime, barroom Gilbert and Sullivan, and the women's nimble-footed Ziegfeld Follies stints.

The effectiveness of Frimlfest also owed much to the imagination and versatility contributed by music director Alice Mikolajewski and stage director Virginia Freeman and the dialogue written by Charlotte Stoudt.

The show, hosted by the Czech Embassy, will be repeated Friday and Saturday at 8 p.m. and Sunday at 5.