Hmmm... not LF but still:
My 2 and a half year old daughter was always fascinated by my sticking my hands in the changing bag while loading up 120 roll film into the tanks. As a reward for "looking but not touching" I would always give her the spindles and backing paper to play with after.
A few months go by, and upon my return from a pre-dawn photo expedition, I plop down about five rolls of Velvia on the table, kiss the wife who is making breakfast for my daughter, return to the table to find my daughter had become so adept with 120 film, in about 30 seconds, she had unrolled and separated two rolls of Velvia - and commenting on the pretty purple color it had turned.
Now if only I could teach her how to load the darned SS reels...