The National Dog Show Presented by Purina is insanely huge and popular. It's been around since the 1800s. It's been on TV since 2001 and draws millions of viewers. Also interesting, the show is taped two weeks before it airs, and even though the hundreds of people in attendance know who wins before the show airs, there has never been an issue with that information being leaked to the public, according to a few people who work with the show.