NEW YORK—Viacom, the global media conglomerate that includes such properties as CBS, Paramount Pictures, MTV, Nickelodeon, UPN, Showtime, Blockbuster Video, and Simon and Schuster, began airing a TV ad Monday that orders its employees to get back to work. "Worker efficiency needed a little boost," said Viacom CEO Sumner Redstone. "But instead of sending an e-mail to everyone at all of our subsidiaries, we just televised a 'Look alive, people' warning during Ricki Lake." The 30-second spot also included a reminder that discussion of Super Bowl pools should occur at breaks only.