Mrs CS was only 11 and had been called as the Jr Primary Pianist in their small ward and desperately needed practice (she only had a couple of months of lessons when she was 4.)

No way they could afford a tuner so Lil Miss CS found a crescent wrench, figured out how to get inside the piano and tuned it herself (she's stubbornly resourceful and has a pretty good ear for pitch.) Needless to say, Youtube DIY videos were still many decades hence so she just figured it out as she went.

Those who don't know her may doubt this story--and those who do aren't surprised.