The very first time I saw computer graphics was on a lame show from the BBC showing what was, I thought at the time, the most spectacular animation ever of a giant robot ant. I hadn’t seen it since 1984, but still had strong memories of it.
It’s here - starting at 2:25.
It’s still pretty good, all things considered.
I had lost all hope of ever watching Mani Kaul’s 1984 film Dhrupad about the dhrupad sub-genre of classical Indian music - until I (mostly out of boredom) did a youtube search: http://www.youtube.com/watch?v=5qqiy5qCTYY. Lo and behold! That was cool, and unexpected.
The old Larry Bird/Michael Jordan “Nothing but Net” commercial. God, that brought back memories.
And Restless Heart’s “Dancy’s Dream.”
My older son happened to be born on the same day that the Winter Olympics opened in Lillehammer, a fact he is reminded of every year when his birthday comes around. This year I mentioned the torch being brought into the stadium by a ski jumper, and he and his younger brother both said they wished they’d been around to see that. So I looked on YouTube, and folks, the whole dang ceremony is there. Starting here. Norwegian commentary, no subtitles, torch-bearing ski jumper is in part 9.
He lands successfully 
I guess not too impressive, but there’ve been a few instances where I wanted to find a specific In Living color sketch, and have been most successful.
I actually found Doot Doot by Freur on YouTube. Never saw the video when I was in school, so that was a treat.
I’m an online new guy. You tube is great for finding old music videos.
this stands out http://www.youtube.com/watch?v=Tbgv8PkO9eo
That’s pretty good. But my favorite Olympic flame lighting ceremony was the 1992 Games in Barcelona where the cauldron was lit by a flaming arrow.
Okay, I have to thank the OP for making me think about this “obscure YouTube” stuff. 
For many years, I’ve been searching online for a particular Men at Work song that’s only ever been played live. We’re talking early 80s here. I had it on a cassette tape recorded from a radio show from 1983, but the tape was lost long ago. I’ve always remembered the song, though, because I liked it and it was never on one of their albums. I could never find it online–the occasional references to it, but never the song itself.
This thread reminded me that I hadn’t checked YouTube for it. And so I did. And there it was!
So thanks, Stoid. You’ve made me a happy camper today.
One day I was reading about a particularly brutal college basketball brawl betwen Ohio State and Minnesota in 1972 (well mostly Minnesota players attacking Ohio State players). I decided to see if there were any video of it.