My Aunt was babysitting me, and took me with her to Lagoon where we watched them play. I was a very young teenager. I think after that my next concert was Tommy James and the Shondells
"Lagoon amusement park, with its Lagoon Patio Gardens stage, hosted everyone who was anyone in the 1960s rock scene. The Rolling Stones, Jimi Hendrix, Janis Joplin, Donovan, Eric Clapton, Jefferson Airplane, Big Brother and the Holding Company (whose "I'm a pterodactyl, dying for your love" is No. 1 in my ranking of strangest rock lyrics), Country Joe and the Fish, Eric Burdon and the Animals ... and the list goes on".
http://www.sltrib.com/sltrib/news/54006251-78/morrison-lagoon-rock-salt.html.csp