Play of the Day -- Rick Perry does Leno; Plus: Mitt Romney is his own mistress

Jon Stewart has discovered that Mitt Romney also has a mistress who is threatening his presidential campaign. "Just like Herman Cain, Mitt Romney has an embarrassing person in his past who he is desperately trying to hide," The Daily Show host joked on Thursday. "For Herman Cain, it's a woman named Ginger White. For Mitt Romney... it's Mitt Romney." Don't miss today's Must See Moment at 2:20 when Jay Leno gets Rick Perry's reaction to the moment when the Republican presidential candidate flubbed the voting age and election date: