DIVERSIONS OF GRANDEUR Trashy romance novels may be perfect for summertime escapism, but fall calls for more enlightened pastimes. Houston delivers with an artistically packed weekend September 27-29, one built for cultural indulgence. Begin Friday evening, when the Houston Ballet performs Madame Butterfly, an adaptation of the operatic favorite. On Saturday visit the Museum of Fine Arts, where you'll see "Masterworks From El Greco to Picasso," an exhibit that features more than fifty works by such artists as El Greco, Cézanne, van Gogh, Monet, Renoir, and Picasso from the Phillips Collection, which is renowned for its Impressionist and Post-Impressionist art. That night, classical music lovers are in for a treat when Itzhak Perlman, donning the hats of both conductor and solo violinist, joins the Houston Symphony for an evening of favorites, including Schubert's Symphony No. 5 and Tchaikovsky's Symphony No. 4. Finish your highbrow weekend Sunday afternoon at the Main Street Theater, where a matinee performance of The Laws of Storms —Thomas Meloncon's play about the Galveston hurricane of 1900—is sure to elicit applause. Bravo, indeed, Houston. See Houston.