What do y’all do w/ old jam jars?

My sister was about to toss her empty jam jar in the bin, so I nabbed it & washed it out instead. I’m an art teacher, so collecting random shit like this is ingrained in me now. I just have no idea what I could use it for, so I ask… how do y’all repurpose old glass jars?

Specifically: Any teachers, artists, or gamers have creative ideas (like turning it into an art piece) or practical ideas (like using it for storage)?