In the mid 1970s, I lived in Easton, across the street from Lafayette College. On the Saturday before final exams, they always had a free outdoor music festival which was not publicized to the general public.
On this particular day, I heard music from my apartment, so I headed over to the quad. The next day I was talking to a co-worker who also was there, and I said "that band sounded a lot like Procol Harum." He said, "That WAS Procol Harum."
It turns out they were near the end of a tour after playing in Philadelphia the previous night, and were headed to New York for a Sunday show. Since they had an off day, they filled in with the Lafayette date.
Procol Harum could really rock out when they wanted to. Check out "Nothing But the Truth."