Cello lessons, from age 8 I think, which I should have continued - quit at 16, partly because of a school change, partly because I didn't really want to play in orchestras. The more bass guitar I play, the clearer I am that those lessons are a key part of my musical mindset. But I never did very much with it. I also did theory, to at least grade 5 (I found the certificate a couple of years ago), but I have no recollection of doing that at all. I've pretty much forgotten how to read music.
I can't remember anything of the curriculum music lessons. Possibly I didn't have to do them? I certainly learned a lot more at home though.
I do remember my parents (both teachers) talking about the sorry state of music education in schools. My dad floated the idea that if the powers that be really hated rock music so much, they should ensure it was taught in school.