They claim to be refugees from Planet A, which circles the star Cappella in the constellation Auriga . . . and who knows? If their sense of fun is any indication, it's probably true. One thing is for sure: when the Edlos take the stage, the quartet of unaccompanied singers never fails to transport entire audiences with their unique combination of outrageous humor and impeccable musicality, post-modern dynamics, and inventive vocal arrangements of everything from Gregorian chants to the songs of the Beach Boys -- as well as bizarre originals like those found on their new album, Just Us. Behind the jokes, costumery, wigs, and other assorted mayhem, Eric Morris, Ed Cohn, Larry Venza, and Craig Knudsen all have stellar reputations as classical performers -- they are veterans of outfits like the San Francisco Opera Company and Pocket Opera, among many others -- but it sure doesn't prevent them from having a good time.