We've known since April that David Letterman is stepping down from his position as host of the 'Late Night' show, but we didn't exactly exactly when the host would change to Stephen Colbert until recently. Mark this date: Letterman's last day will be May 20, 2015! So, looking forward to this change, I've decided to put together some of my favorite Letterman moments! 1. Madonna and Letterman: 1994 Edition 2. Letterman's Monologue on 9/11 3. John McCain's No-Show 4. Johnny Carson Tribute 5. Dave at Taco Bell 6. Compilation of 10 most awkward interviews!