In Origin Story, LateNighter digs into the people, ideas, and happy accidents behind some of late night’s most memorable bits.
Three months into Late Night with David Letterman, a Viewer Mail question arrived from Kirk Hancock, who wrote on behalf of “the guys in my dorm.”
“Is there real glass in the window that overlooks the city behind your desk?” Hancock asked on the May 7, 1982 episode. “For that matter, is it a real city that overlooks your desk from behind the window? On the other hand, is the desk that is overlooked by the city on the other side of the window real? We are so confused. Please clarify.”
If nothing else, Letterman observed, the letter confirmed that college kids had too much free time on their hands.
Then he answered the question the only way he needed to: by nonchalantly tossing a pencil over his shoulder.
The sound of breaking glass told Hancock and his dormmates everything they needed to know. A second pencil toss—and a second crash—confirmed it.
The joke is credited to original Late Night writer Stephen Winer, though he tells LateNighter he didn’t think much of it at the time.
“I didn’t think it was a great joke even then,” Winer says.
In Winer’s view, the audience didn’t seem to think much of it either.
“It didn’t get much of a laugh,” he says of the first toss.
But Letterman broke two more windows that night, then threw three more pencils the next day.
“And we all realized that was going to be a thing,” Winer says.
The breaking-glass gag was simple, but it worked on several very Letterman-specific levels.
For one thing, it was absurdist.
“The thing about the Letterman show was that eccentricity was its baseline,” Winer says, noting that he couldn’t imagine The Tonight Show Starring Johnny Carson doing a similar bit. “Which is nothing against Johnny Carson—it just wasn’t his style.”
It was also a textbook example of a comedy principle familiar to anyone who watched Letterman long enough: a joke could be funny, then not funny, then funny again through sheer repetition.
Winer has his own name for the phenomenon. He calls it Pavlov’s Rule of Comedy.
“If you repeat a joke often enough, people will recognize it as a joke and laugh, even if they didn’t think it was funny the first time,” he says.
That is more or less what happened with the pencil.
Over time, the gag mushroomed. Letterman regularly launched pencils, blue cards—and whatever else happened to be on his desk—through the windows behind him. Guests frequently asked if they, too, could throw a pencil through the window. Not all of them were successful.
To protect anyone who might get in harm’s way, Letterman’s staff eventually began stocking his desk with pencils that had erasers on both ends. The double-nubbed pencils served a practical purpose, but they were also an homage to Carson, who famously drummed his Tonight Show desk with similar pencils.
By the time Letterman moved to CBS and the Ed Sullivan Theater, the bit had become something more than a bit.
“The audience was four times larger,” former head writer Steve O’Donnell recalled in Brian Abrams’ And Now… An Oral History of Late Night with David Letterman. “It had almost become sort of a religion in a way, which can be deathly.”
Like dogs salivating at the anticipation of a bell, O’Donnell said, the larger crowd “was just waiting for Letterman to throw the pencil and hear the crash.”
As a one-off answer to a ridiculous Viewer Mail question, the breaking-glass bit was an unlikely candidate for an enduring Letterman ritual. But comedy writers know the story well: It was rarely the joke you slaved over that stuck. More often, Winer says, it was the throwaway that happened to tickle Letterman’s fancy.
“It is strange about what jokes endure and which jokes don’t,” Winer says. “And it doesn’t even necessarily seem to be because it’s the funniest joke. It’s just there’s something about it that makes it live on.”
The pencil gag’s longevity, though, is no mystery to him.
“It was that Dave kept doing it.”
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