When Silence Falls, The Murmuring Begins...
A meme floating about the interwebs states:
"On August 29th, 1968, all the televisions in America shut down. There was a murmuring on the TV that some believe was the devil's voice. The televisions were off for about 25 seconds. No one knows what the issue was an no one knows what the sound was from the TVs."
I cannot corroborate that any such event--an inarguably remarkable one--occurred, which is surprising. There were significant power outages in both 1965 and 1968 that blacked out large portions of the country. UFO conspiricists love to mull over those. And it does remind me of the Doctor Who episode "The Impossible Astronaut" about an alien species known as The Silence that is set in 1969.
However, if the meme is real, it is interesting to note that this would have transpired one day after a famous antiwar protest at a Democratic National Convention in Chicago. The same antiwar demonstration that gave rise to the popular protest slogan: "The Whole World Is Watching."
UPDATE: It may appear that this is yet another amalgam of half-truths. On April 10, 1961, television broadcasts were suspended briefly for a civil alert test. Prior to termination of all transmissions, the following was aired: "We interrupt our normal program to co-operate in security and civil defense, as requested by the United States government. This is a Conelrad alert. Normal broadcasting will now be discontinued for an indefinite period. Civil Defense information will be broadcast in most areas at 640 or 1240 on the AM dial..."
As you can hear from this recording from April 28, 1961, the audio is definitely drifting into what one could construe as murmuring:
Moreover, there were articles from 1968 in various newspapers that mention strange signals from space, as picked up from the Arecibo radio telescope in Puerto Rico that piqued the interest of Dr. Frank Drake (famous for his eponymous equation for the probability of extraterrestrial life).
This story may also be confusing an incident that happened at 5:10 pm on November 26, 1977 when the Hannington transmitter of the Independent Broadcasting authority in the UK was hijacked by a speaker claiming to be a representative of an "intergalactic association". The speaker who has been reported as calling himself "Vrillon" or "Gillon" or "Asteron" (depending on whom you ask) spoke with a disguised voice to warn those watching that their "weapons of evil" must be removed and there is only a "short time to lear to live together in peace." Fortean Times magazine's Winter 1977 issue (#24) has the verbiage a bit different, but the sentiment remains the same: "This is the voice of Asteron. I am an authorised representative of the Intergalactic Mission, and I have a message for the planet Earth. We are beginning to enter the period of Aquarius and there are many corrections which have to be made by Earth people. All your weapons of evil must be destroyed. You have only a short time to learn to live together in peace. You must live in peace... or leave the galaxy." The hoaxer was never identified and the incident remains a mystery.