Last real festival I went to was Atlanta Pop Festival, in 1970. There was one in 1969 also, but Woodstock over-shadowed it. Since I didn't go with my friends to Woodstock, I wasn't going to miss Atlanta Pop Festival.
I saw B.B. King, Mountain, John Sebastian, Procol Harum, and Jimi Hendrix, just to name a few. I missed several groups because of being at the river (about a mile away), skinny-dipping with about 20,000 other people. It was a real hoot! The festival was July 3, 4, & 5, 1970. Do a Google search, and you'll find a good bit of info about it.