Welcome to Night Vale is the number one most downloaded podcast on iTunes. Jeffrey Cranor & Joseph Fink hide caption

itoggle caption Jeffrey Cranor & Joseph Fink

Conan O'Brien interviews Bruce Willis in a 2005 episode of Late Night With Conan O'Brien. NBC/Getty Images hide caption

itoggle caption NBC/Getty Images

Jay Leno delivers the opening monologue during the inauguration of The Tonight Show with Jay Leno on May 25, 1992. Craig Fujii/AP hide caption

itoggle caption Craig Fujii/AP

David Letterman, pictured here in January 1982, premiered Late Night With David Letterman just a few months after his Fresh Air interview. AP hide caption

itoggle caption AP