Earth Day always reminds me of an Earth Day gathering I attended in Boston back in the early 1980s (or was it the late 70s? things back then were a bit fuzzy sometimes...)
There was a big gathering/concert/festival at a public park area--I think it was somewhere at the Boston Commons--with a number of performances by local groups and a number of fairly well-known bands. They were starting off with an ecumenical religious ceremony including representatives from all sorts of religious groups, from Christian to Jewish to Buddhist to Pagan and everytning in between. A good friend was coordinating the religious opening event and was bemoaning the fact that it was hard coordinating all these different groups and get them to listen to directions and get them on and off the stage at the same time. She observed that the bands all had stage managers to handle this sort of thing for their performances, which made all go smoothly.
I was still involved in theatre at the time, and volunteered to act as her "stage manager," which I did. Our part of the festivities was the first thing on the program, and indeed, we did get all the groups on and off the stage and coordinate their participation and keep everyone playing nice. Backstage I saw some fairly big-time musicians, their stage managers, roadies, journalists, and other persons, all milling about the best table of snacks & beverages I've seen this side of anywhere. I was a "roadie", too, so I was "cool."
That's what I always think of when Earth Day rolls around.
P.S. Oh, yeah, and stage managers rock!