I remembered some more.
If you were involved in the theater department, after the spring play, all the seniors got to paint their name and graduating year on the wall backstage somewhere. There are names written backstage that go back to the 1950s . . . it's really cool to see all the people who have done theater there, and I hope to come back someday when I'm old and see all the new names.
We had Homecoming in the fall, complete with Spirit Week, powderpuff football, a parade with floats, Homecoming Court, a pep rally, the football game and a dance. Around Valentine's Day, we had a similar thing (a little bit more low-key) called TWIRP, which stood for The Woman Is Required to Pay. (This is apparently a Wisconsin thing, since I know a bunch of other kids who went to high school in Wisconsin and also had a Sadie Hawkins-esque dance called TWIRP, but nobody in any other state that did.) TWIRP had Spirit Week, a pep rally, a dance and TWIRP Court. I was on TWIRP Court as a senior, but I don't like to tell people that because "TWIRP" sounds so silly.