My senior year, my German class only met every other day, the other days we had a "free" hour. The German teacher I had during my Sophomore and Junior years took a sabbatical (had a baby) and so, rather than hiring a new German teacher, they had a teacher from another school come to our school in the afternoon — particularly as each class was very small (only 6 of us in my class).

The issue was, she had two classes — one at each school — during 4th period (the one that included lunch). So, every other day (at least at the start of the year) we had an extra long lunch period. The school finally (after 2 or 3 months) realized we didn't have any class every other day, so required us to go to the library for "class" — we were assigned a room inside the library to meet each day. It was a fun year.

I actually voted computer tech — because this was the mid-70s and high schools didn't have computer classes (PCs weren't a thing yet — the Altair kit was just starting to be sold). It was a programming class, we programmed in RPG3 on an IBM mini computer that was still as large as a table. We had to punch cards — it used the small 96 column IBM punch cards. Even more crazy, you had to run a couple of thousand of those cards through the machine to boot it.