Showing my age here, but when I was in high school, I did the teaching. Mostly to fellow students, but I did have two of the math & physics teachers in my "class" off and on. I taught Pascal on an Apple II. A little later, the high school down the road from mine actually set up proper programming classes (teaching Basic on Commodore computers). A bunch of work colleagues who are about my own age had similar experiences -- few high schools were set up to teach anything about computers at the time, so the nerds amongst us got to see the "other side" of teaching.