In brief, the original spring thing was Color Day, c1902-1938. (Hartwell closed it down in his era, thought it was getting out of hand!) Color Day was a sort of May Day, and I think some years coincided with Apple Queen events etc. The day was more or less as follows: a baseball game, a pageant (girls dancing around a May Pole, costumed students playing Rip Van Winkle...) a picnic, and a dance in the evening. I actually have 40 minutes or so of digitized home movie footage of Color Day in the '30s.
I think what followed that up at some point in the '40s was "Spring Day," which was at least in part, if not largely, a student recruitment event.
The Daisy Chain was a separate thing, I think it ran c1947-1964, something like that. That was where a group of junior women carrying daisy chain garlands preceded the seniors as they paraded to Hartwell Hall for graduation, I think many years they started at the Roxbury, or Baptist Church.
Then of course there was the famous, or infamous, Spring In of the '70s, the Genny beer trucks on the mall etc.!