Remember Chuck Percy? The former Republican senator from Illinois may have been ejected from office by the voters, but he left at least one enduring legacy: the Capitol Steps musical comedy group, cofounded by Percy aide Elaina Newport to entertain at a 1981 Christmas party in the senator's office. "We had thought of putting on a traditional nativity play," the Steps explain in the liner notes of their most recent album, 76 Bad Loans, "but in the entire Congress we couldn't find three wise men or a virgin." The troupe, making its local stage debut this weekend (though it's already won a large local following via its appearances on National Public Radio's "All Things Considered"), consists of current and former aides to politicians from both sides of the aisle, and its blunt and bitchy song spoofs are appropriately bipartisan. Targets include Ted Kennedy ("Fun, Fun, Fun 'til Teddy Puts His T-Shirt Away"), Vice President Quayle ("Talk Like a Dan"), President Bush ("Fifty Ways to Hide New Taxes"), and liberal political-correctness enforcers ("You Dont Bring Me Floriculturally Diverse Polyfragrant Soilistically Challenged Multipetaled Victims of Pesticidal Food Chain Chauvinism"). But the nasty lyrics are only half of it; much of the Steps' humor also derives from their improbably eclectic juxtaposition of songs--by the likes of Paul Simon, the Beach Boys, and Neil Diamond with material from shows ranging from The Music Man and West Side Story to H.M.S. Pinafore. And turning bad news into belly laughs isn't this ensemble's only contribution to society: "We like to say we're a public service organization," Newport notes, "because we took five lawyers out of practice." Centre East, April 25 (7701 N. Lincoln, Skokie, 708-673-6300). Saturday, 7 and 10 PM. $17.50-$25.