The first day of MTV: August 1, 1981

The first day of the end of music... MTV launches a thousand techno-geeks-with-synthesizers into our faces, destroying forever the organic tradition of music-making we had so enjoyed from Woody Guthrie to the Mills Brothers to Aretha Franklin to Steely Dan to Donna Summer... or something.
Believe it or not, American Express was a co-owner of MTV!  And allegedly, they wouldn't play music videos by black artists.  "Video Killed the Radio Star" was the first video played (I hesitate to call it a MUSIC video).
The first day's festivities aired out-of-order, too, thanks to wacky automation software, which I believe really just consisted of a big rubberband.
Nice touch with the Pioneer reel-to-reel in the background... ALREADY obsolete in 1982.  I think the last new mainstream reel deck model came out the year before, the dreaded (due to its flimsy drive system) and wonderful (because it looked cool and sounded pretty good) Akai GX-77.





Here is a pretty great video explaining why they don't play videos anymore.  NSFW, and they finally call out Napster!