AT THE TURN of the 20th century, Iowa's Cherry Sisters - Ella, Lizzie, Addie, Effie and Jessie - were an unbelievable singing act. Their show was so breathtakingly ill-conceived and ill-performed that people flocked to marvel at how bad they were, and to throw rotten vegetables at them.

It wasn't just their voices - the aptly-named Cherrys were also virginal sourpusses who performed to "uplift the stage" by means of righteous songs and bizarre skits including, of course, their nightly onstage crucifixion. They usually ignored the boisterous heckling, but if the audience got too rowdy, Ella or Addie had a loaded shotgun ready to wave.

In an 1898 review so scathing that the Cherrys sued (and lost), one journalist called them "three creatures surpassing the witches in Macbeth in general hideousness" and said it was "impossible to burlesque the Cherry girls. They are nature's own raw material, unique and inimitable."

What the Cherrys saw as libel, Philadelphia's Jennifer Childs must have heard as a challenge, for she literally burlesques the sisters in Cherry Bomb: The Worst Act in Vaudeville for the Holidays. Childs created this off-kilter musical confection with composer James Sugg. It's been described as a musical bonbon with a vaudeville center.

If anyone can succeed at staging "nature's raw material," it's Jennifer Childs. Granddaughter of a vaudevillian, she's the artistic director of 1812 Productions, the all-comedy theater company she founded (with Peter Pryor) in 1997 and for which she's been putting together holiday shows and more for 10 years. She's also one of Philadelphia's most celebrated comic actresses, so she knows her way around the stage.

She also knows what she likes - and doesn't. "One of the things I hate about reality TV," she said in a recent interview, "is our fascination with watching people do bad work and/or humiliate themselves." With cases like William Hung or other famous-for-being-bad figures (see sidebar), "people sort of lose their identity and become just these comic pop-culture figures," Childs said.

She decided to explore that phenomenon and try to find the real people behind the Cherry Sisters legend.

In addition to the sisters, one of the intriguing real people in Cherry Bomb is Oscar Hammerstein, the grandfather of Richard Rodgers' partner and a Broadway impresario. Though the Cherrys made their own name in Iowa, it was Hammerstein who made them enduring Broadway stars.

After a string of failures at his Olympia Music Hall, Hammerstein was ready for a game-changer, and having already presented the best talent, decided to "try the worst." So the Cherry Sisters opened on Broadway and packed the house. To get New Yorkers up to speed, Hammerstein had stagehands and members of his family in the audience with vegetables to throw. He then assured the Cherrys that this was the work of rival acts jealous of their success.

Hammerstein, the svengali who turned the Cherrys into "comic pop-culture figures," appropriately serves as the emcee for "Cherry Bomb," opening the show with a tune called "Try the Worst." He sets up the story and introduces the diverse acts, which range from straight singing to melodrama, burlesque, dramatic reading and even a juggling routine.

Obviously, telling the story of these stranger-than-fiction personalities calls for a creative touch above and beyond the ordinary. What, after all, makes "bad" funny? And how do you do a show about awful performance that's not unpleasant to watch?

"One of the things that I think is really important is that you can't try to be bad," Jennifer Childs said. "It's the things that happen that are unintentional badness - or seemingly unintentional badness - that really make us laugh."

"Sometimes," she said, "it's something as simple as no stage presence." In fact, Fred P. Davis observed, in the Cedar Rapids Gazette in 1893, that "their knowledge of the stage is worse than none at all." Childs wondered, "OK, how do you act that?"

One handy hook on which to hang a comic interpretation is the Sisters' holier-than-thou attitude. "So many of their songs," said Childs, "are about 'We're so much better than everybody else, and nobody else sees it.' " That's helpful - if we felt too sorry for these incompetent performers, she noted, we'd be less likely to bust a gut at their expense.

A deadpan demeanor also helps. "They never smiled," Childs assured me. "Even when they were singing 'Ta-ra-ra Boom-de-ay,' they were humorless, absolutely humorless. And there's something funny about that."

As for making a full evening of "bad singing" not excruciating to sit through, composer James Sugg said that he employed "moments and tricks to go just outside the realm of normal." These include exploiting and emphasizing any peculiarities of the cast members' voices, setting their parts extra high and low to create a harmony with "a hollow center" and setting words so that the accents fall on the wrong musical beat. The show is "highly tuned entertainment," he was quick to note, "but we try to find the little ways of illuminating the badness with a bit of goodness."

Finally, though, everyone still wonders: How could these women have a career based on their terrible singing and not notice it? Didn't they really know all along, and were they just playing us all for chumps?

After years of exhaustive research, Childs tentatively endorses the Sisters' sincerity. Especially after reading Effie's autobiography, "I cannot believe for a minute that it was an act."

But, she added, "I also don't think they were stupid. They were smart enough to figure out that when we go out and do this, people give us money, so we're going to keep doing the same thing."

A lifetime of catcalls and hurled produce must have had an effect, though: Effie wrote a song, "Scatter Roses at My Grave," which has been re-created for the show (while the Sisters' lyrics survive, their original music is long gone). Childs summarized it as: "When I'm here with you on earth, that's when I need your kind words, but if you can't be nice to me here, at least when I'm gone, speak well of me and scatter roses on my grave.

"And to me there was just something very beautiful about these women who had had tomatoes and eggs thrown at them their entire lives asking to have roses thrown at them instead."

Cherry Bomb is certainly a far cry from roses. But for these "unique and inimitable" ladies, it's probably a better tribute than they could have hoped for. *

"Cherry Bomb: The Worst Act in Vaudeville for the Holidays," Plays and Players Theatre, 1714 Delancey St., Dec. 11-Jan. 4, $17, www.1812productions.org.