On May 9, 1961 Newton N. Minow addressed the National Association of Broadcasters in Washington, DC. President John F. Kennedy had recently appointed Minow to the chair of the Federal Communications Commission. To the assembled executives of broadcast television he said:

I invite each of you to sit down in front of your television set when your station goes on the air and stay there, for a day, without a book, without a magazine, without a newspaper, without a profit and loss sheet or a rating book to distract you. Keep your eyes glued to that set until the station signs off. I can assure you that what you will observe is a vast wasteland.
You will see a procession of game shows, formula comedies about totally unbelievable families, blood and thunder, mayhem, violence, sadism, murder, western bad men, western good men, private eyes, gangsters, more violence, and cartoons. And endlessly commercials—many screaming, cajoling, and offending. And most of all, boredom. True, you’ll see a few things you will enjoy. But they will be very, very few. And if you think I exaggerate, I only ask you to try it.

You can read the text and listen to the audio of that speech, which took the broadcasters to task for failing to serve the public interest even while they used the public airwaves.
Minow’s positive contribution to public-spirited television was the creation of the presidential debates. With co-author Craig L. LaMay he recounts that story in Inside the Presidential Debates: Their Improbable Past and Promising Future. See some memorable moments from the presidential debates and read an excerpt from the book.