Just remembered this, and wondering if I was the only kid who did it: I kept an emergency kit with me when I was young in case I got sucked through a dimensional portal, which seemed to happen all the freaking time in books and TV shows. I fit it into a box of kitchen matches, since that seemed pretty compact. The kit included a spool of twine, matches, a mirror, first aid supplies, a golf pencil, and (because I couldn’t figure out how to pack rations that were both compact and non-perishable) packets of duck sauce.
Anyone else, or just me?