Know the old bumper sticker "If you can read this, thank a teacher"? That's what comedian Dave Chappelle did Sunday night at the 69th Primetime Emmy Awards, and John Oliver picked it up and turned it into a Twitter hashtag.

It all started when Chappelle, while presenting the best comedy director award along with Melissa McCarthy, cracked that he'd skipped rehearsal and was just going to read the teleprompter. "Shoutout to D.C. public schools," joked Chappelle, who was born, raised and educated in the DC area.

The audience laughed appreciatively, but the joke gained new life later on, when Oliver's "Last Week Tonight" won a writing Emmy.

"I would like to unexpectedly thank D.C. public schools, just to get it trending on Twitter for no reason," Oliver announced.

And so he did. Almost immediately, the hashtag #DCPublicSchools was trending nationally on Twitter, with many thanking Oliver for drawing attention to the importance of education.

John Oliver's acceptance speeches are the freaking best... He needs to win every year for as long as possible. #DCPublicSchools #Emmys — But Her Race (@butterrace) September 18, 2017

#DCPublicSchools trending in less than a minute, go John Oliver #Emmys — The Bull Moose (@TheBullMoose2) September 18, 2017

Well if he said to do it so I'm gonna do it #dcpublicschools pic.twitter.com/xRnCIgP5t6 — shoe (@Philip07235) September 18, 2017

I actually am a #DCPublicSchools graduate. Long overdue #Emmys recognition. — Frank Rich (@frankrichny) September 18, 2017

What if y'all supported #DCPublicSchools students & teachers w/ FUNDING & SUPPORT and not just hashtagged tweets cuz @iamjohnoliver asked. pic.twitter.com/4w5bruUtPm — Britni Danielle (@BritniDWrites) September 18, 2017

And even though Sunday isn't a school day, someone from the DC Public Schools social media team was smart enough to respond.

What an unexpected honor! We'd like to thank our educators, our families, and of course, our amazing students. #emmys #dcpublicschools — DC Public Schools (@dcpublicschools) September 18, 2017

It wasn't DC's first moment in the CBS broadcast Sunday. Former White House Press Secretary Sean Spicer surprised many by coming out with a motorized podium as part of an opening-monologue joke. (Disclosure: CBS is CNET's parent company.)

Tech Culture: From film and television to social media and games, here's your place for the lighter side of tech.

Batteries Not Included: The CNET team shares experiences that remind us why tech stuff is cool.