My search landing on this page which is a fun little read through Twin Cities music history. My parents moved here in 1969 and I was only 9 years old. Looks like I missed a lot of fun!
http://www.jeanneandersen.net/musichighlights.html
Apparently in 1967 Minneapolis was pretty cool -
KDWB and the Aquatennial sponsored "Happening '67" at the Minneapolis Auditorium. It was a "three day psychedelic feast," held on July 19-21. Sheets of brilliant silver mylar and colorful fabrics decorated the auditorium. Performers were Jefferson Airplane, Buffalo Springfield, the Electric Prunes, and the Shadows of Knight.