Once upon a time, in the early 70s, Grease was a humble little show–a loose collection of sketches and comic songs by Jim Jacobs and Warren Casey performed at Kingston Mines. But it became one of the first big hits of Chicago’s burgeoning off-Loop theater scene, and in the middle and late 70s–thanks to the intervention of bigger theater fish–it became a Broadway hit, then a film vehicle for John Travolta and Olivia Newton-John. Finally, at what I assumed was the show’s nadir, came schlockmeister Tommy Tune’s silly, slapdash version, drained of all its edge and charm and starring a dazzling array of no-talents (Brooke Shields, Debbie Gibson, Sally Struthers). But Grease on Ice is the flattest, most cartoonish version yet–and the campiest and most surreal. Of course, Nancy Kerrigan is the least likely Sandy ever: Kerrigan is such a strong, assertive skater that we’re never for a minute convinced that she’s the sweet, shy, too-good-for-her-own-good new girl. More important, the whole genre of shows on ice depends on conventions even more artificial than those governing other kinds of theater. All the dialogue in the show is prerecorded and the actors are on skates at all times–essentially they lip-synch their lines, which makes them look like life-size puppets or actors in a poorly dubbed foreign movie. All the dance numbers have been transformed into intensely choreographed, awesome skating numbers, many of them involving a dozen or so performers in feats so dangerous they’d make a Blue Angel faint. But oddest of all is the circuslike atmosphere: the sports arena where I saw the show was packed to the rafters with Nancy Kerrigan T-shirts, Greased Lightning bolts, and faux Barbie dolls made up to look like Sandy. Yet the most excited scream I heard all evening came during intermission: a group of preschoolers squealed, “Oh, mommy! Look!” when the Zamboni lumbered out to smooth the ice. United Center, 1901 W. Madison, 312-455-4500 or 312-559-1212. October 1 through 3: Friday, 8 PM; Saturday, 1:30 and 7:30 PM; Sunday, 1:30 PM. $15-$75. –Jack Helbig