At the risk of sounding like a curmudgeonly old man, I can remember when the only way to see a musician play was to wait for them to come to my town, buy a ticket, and go see the show. Through the miracle of YouTube, I can now see just about anyone I want without leaving my fortress of solitude. And when I stop to think about it, that's pretty amazing - and I spend more time than I probably should watching concert footage of a wide variety of bands and artists.
For my Saturday "dash of happy", I'll pick Eric's Johnson's "Righteous". He's an amazingly-talented guitar player - and as someone who occasionally picks up a guitar, watching someone of this caliber partly inspires me, and partly makes me feel like I have five thumbs on each hand. It mostly inspires me. And makes me very happy to be able to watch such talent.
Addendum: if you like this clip of Eric Johnson, check out his cover of Jimi Hendrix's "Are You Experienced?", from the same concert.