Phantom Fans Week, an inaugural five-day festival that includes a masquerade ball, begins Wednesday. “Phantom of the Opera” fans will receive behind-the-scenes access to “Phantom: The Las Vegas Spectacular” and the cast. The package includes a keynote address by honorary guest and legendary director Hal Prince. The ball will be at The Venetian’s St. Mark’s Square. Prices range from $250 to $475. Information: www.PhantomLasVegas.com.