Although one of their national leaders once used his shoe to bang on a table, Bolshoi Ballet members apparently make more graceful use of their slippers. And they showed off all that talent and beauty performing at the Mann Music Center, where an openingnight party was held last week for the troupe. A chorus line of notables were among the aficionados at the gala, taking in the shoe business, including (from left) Mann board member Ted Rosen and wife Toni; the board's George Bernstein and his wife Phyllis; and Ted and Vivian Young.