Cellar Darling just did last sunday a "Pay what you want" concert, streamed on YouTube for free, with open donations for anyone who wanted to contribute. They were in the studio, cams pointed on them, and played while 1500 people (me included) was watching.
It was a lot of fun, even though the real thing is obviously better. I think it must also be a bit weird for the bands who are lve streaming - to them it's a rehersal, they're alone in the studio, but they have the abstract knowledge that a lot of people are watching.