'Off-Season' is only on half of the time by Ed Siegel
GLOUCESTER -- Israel Horovitz and Terrence McNally are not playwrights one would think go hand in hand, but they are, says Horovitz, "the oldest of old pals." So it isn't that surprising that Horovitz could convince McNally to write a new play that would accompany a new play of Horovitz's at the Gloucester Stage Company, which he runs.<br /> Too bad he couldn't talk him into writing one with more substance than an in…