I built a theremin in the early 80s for a school project. Had to get the local library to obtain books and other printed resources on it so I could make one. Sadly no pictures survive, and the device itself is long gone. Didn't think to document it at the time, beyond the hand in materials for the project. I was 14. I have wondered about getting a modern one though. They're so cool.
I went to first school (3 tier system, first, middle, high) in the 1970s and we played conkers in the school yard in the 1970s, and into the mid 80s in middle school too. By the time I reached high school they'd been banned.
I see parents and children collecting horse chestnuts in the local market square and arboretum still today though, and it brings back fond memories of rapped knuckles and entanglement "clingy-niner's" or "clinchies" in some games, depending who you were playing with.
That's a colossal number of tapes. The few I found that had been stored in boxes since the 80s had mould on them, hopefully the collection doesn't have mould.