Yes, the Eagles, and Gentle Giant at the Minneapolis Armory on September 23, 1972, presented by Howard Stein and Owen Husney.  The Eagles were up first, Gentle Giant second.  Or vice-versa.  Seems to be no consensus.

Comments from Facebook:

“Yes come out of a space-ship-looking lit-up-pulsing pod-thing, where they returned to when they were finished…I also recall the drum set had wings and floated upward.”

“One of the great things about this concert was that there were no chairs on the main floor so I went and sat just about as close to the front as possible. It also cost only $3.50 as far as I can remember – perfect for a college kid’s budget.”

“The Eagles played an acoustic set of Chris Hilman songs. I had not heard of Gentle Giant and found them like elves playing enchanting music and dancing about. Then Yes appeared and the audience just melted into the floor. They changed my musical tastes forever. I saw them on the same tour in Dallas the following April. A good show but nothing like the group of us on the floor in Mpls.   A small but passionate crowd.”

Courtesy Owen Husney!