Synchronized singing and dog-paddle choreography suit the swimming-pool venue of Jay Paul Skelton's splashy revival of The Frogs, Stephen Sondheim's irreverent 1974 musical version of Aristophanes' comedy. But for all the slapstick, the show's essentially a plea for humanity in hard times: theater god Dionysus journeys to Hades where Shaw and Shakespeare vie for the opportunity to return to earth and bring hope to a democracy mired in pointless war (Vietnam then, Iraq now). Unfortunately, in Nathan Lane's recent revision, which is 45 minutes longer, the songs pad more than propel the odyssey. Returning to the show's natatorium--the leaner original played here in 1988--this latest Sondheim by Pegasus Players combines cunning performances, enormous energy, and, alas, lousy acoustics. --Lawrence Bommer a Through 6/3: Thu-Sat 8 PM, Sun 3 PM, Truman College, 1145 W. Wilson, 773-878-9761, $17-$25.