That joke in “Romy & Michele: The Musical” is also the single best development, such as it is, that the mediocre show could spring onto the film that is its source material. The other laugh lines are lifted verbatim from the movie (yes, it came out in 1997), in which a pair of sweet dingbats played by Lisa Kudrow and Mira Sorvino try to boost their social status at their 10th reunion by pretending to be successful entrepreneurs who invented Post-its. This similitude is understandable since the original screenwriter, Robin Schiff, wrote the book. It’s also frustrating because the show doesn’t stand a chance to work on its own, especially since the journeyman score by the married team of Gwendolyn Sanford and Brandon Jay, does nothing to spark things up. (Admittedly, the orchestra is hampered by a tinny, muddled sound reminiscent of an old Nintendo game; this pushes the vintage vibe too far.)