With all of the talk about late-night Jimmys — Fallon and Kimmel — or the latest news regarding Chelsea Handler, what about the old man leading the clubhouse today? Yeah. What about David Letterman.

Leave it to CBS Sunday Morning to shine a light on its resident network funny man, and the funny men (mostly men) who write for Late Show with David Letterman. Susan Spencer’s report, “What’s So Funny,” actually delves a little deeper. Just a little bit deeper. After first interviewing Late Show writers Bill Scheft, head writer Matt Roberts and Steve Young, the latter describing the show’s efforts to “hit the midpoint of smart and silly,” Spencer ventures to Harvard University to speak with psychologist Joe Moran at the Center for Brain Science. Moran is studying humor from the perspective of brain waves and neural activity. And then she meets with Scott Weems, who wrote a new book on comedy, “Ha!” No. That’s the title of the book.

Spencer also awkwardly stands onstage in an empty Comic Strip Live to demonstrate why she’s not a stand-up comedian.

So enjoy that, too. This is your TV news feature tied to April Fool’s.

Roll the clip!