IT'S NOT JUST THE CLUES THAT ARE BLUE
Parents have managed to develop a mysterious immunity to the virulent cheer of their kids' entertainment. Childless STEVE BURNS, 27, was not so lucky. As host of Nickelodeon's relentlessly upbeat Blue's Clues for five years, Burns put up with all manner of manic happiness, but last week he bitterly announced his departure from the show. "I didn't really want to become Krusty the Klown in front of the nation," said Burns, who, along with animated dog pal Blue, helped teach kids deductive reasoning while prodding them into spending $1 billion on Blue's...