There are two:
Dec 3 1973 - The Who - Quadrophenia tour, Boston Garden (the old one)
Dec 9, 1974 - Genesis - Lamb Lies Down On Broadway tour, Music Hall, Boston
Rush, Dylan, Skinny Puppy, Dead, Ringo, Beach Boys have all been close seconds but those two stand out.
Dec 3 1973 - The Who - Quadrophenia tour, Boston Garden (the old one)
Dec 9, 1974 - Genesis - Lamb Lies Down On Broadway tour, Music Hall, Boston
Rush, Dylan, Skinny Puppy, Dead, Ringo, Beach Boys have all been close seconds but those two stand out.