I've said it before here. My first concert.
Cat Mother and The All Night News Boys (produced by Jimi Hendrix)
Chicago Transit Authority (later to just be Chicago)
Jimi Hendrix.
That's about as weird as it got for me, except my second concert
Brian Auger & Trinity
Elvin Bishop Blues Band
The Chambers Brothers
Led Zeppelin
Plus they did two full sets in that rotation. My friend and I talked with Robert Plant for about 10 minutes between the rotations.