U2 at Massey Hall in 1983. It was the "War" tour. They weren't well known at that point - we bought tickets the day of the show. They were also still professing Christianity and there was a big "John 3:16" banner across the balconies. But Holy shit the energy!
They began to blow up on "The Unforgettable Fire" tour the next year. They played Massey again at the beginning but by the end they were playing much larger venues.