Sorry I can't embed this video here but it's worth going over to this page to watch. It's a 70+ minute discussion with folks who worked on David Letterman's show(s) and the interrogator is Regis Philbin. Interviewed are Exec Producer Barbara Gaines, Director Jerry Foley, Writers Steve O'Donnell and Steve Young, and Stage Manager Biff Henderson. If you're interested in Dave or just in how talk shows happen, it's worth the time and clicking.