A live jam* by Pink Floyd in the BBC studios during coverage of the Apollo 11 landing (by then, even the BBC had bought into the 60s). I watched the BBC coverage, but don't remember this - I assume it was transmitted after the LEM touched down and my sister, brother and I went to bed. A few hours later, my mother shook us awake: because Armstrong and Aldrin couldn't sleep, the moonwalk had been brought forward to 4 am British time.
An article in today's Guardian describes how the BBC nearly missed the crucial moment:
"I stayed in the studio, because I had nothing else to do, listening to the air-to-ground transmissions from Houston," says Burke [one of the presenters, long with Patrick Moore and [EDIT, see comments] Cliff Michelmore]. "And after about half an hour, Armstrong and Aldrin started doing the kind of thing you do if you're going to get out. So I went upstairs and said to the guys, 'Look - they're going to get out.' They all said, 'No they're not - the flight plan says they're not.' I said, 'Well, they're doing all the things they'd do if that was about to happen.'"*EDIT The audio is a recording of the live jam; the video is a collage of various lunar excursions.
You can imagine the next bit being enacted amid a sea of paper cups and discarded scripts, in standard-issue BBC accents. "There was a long pause, and somebody said, 'You do understand that this means us broadcasting all night?' This had never happened before in the history of television. I said, 'Well, you know, if you want to cover it ...'"They said, 'OK - but if we stay open and nothing happens, you'll never work again.' So we did it, and we had to go to Alexandra Palace." A car was called, and Burke sped to north London, where he readied himself to talk the viewing public through the images that would soon be relayed to Earth.