Guitar strings

One of the things guitarists have to do is regularly change their strings, which are metal and can be recycled, but I am wondering if anyone has any creative ideas for up-cycling them or re-using them in a way that hasn't occurred to me. Any ideas out there?

I have never done anything specific with them, I just use them as really nice wire.

I suspect you could make a door chime with things that hit the strings when it moves...
Something like this random pic off the net

I just used them for making jewelry when I was a kid. I grew up surrounded by musicians, so I was awash in strings from various instruments. It's worth unwinding the heavier gauge bass strings to get the fun, twisty wrap wire. Strings have a core of wire that's got another wire coiled tightly around it, which you can pull off.  Mostly, on bass strings, they're roundwound, so it's just a regular wire wrapped around the core. There's also flatwound, so the outer wire is like a strip of ribbon coiled flat around the core. There's groundwound and halfround strings, too, but I never got any of those. Some guitar strings have a nylon core, so you'd want to keep that in mind for some uses.

Once I got a bit older, my penniless friends would scrounge used strings from my family cause they were better than the very used ones they had.

Well-cleaned, they can be used for cutting cakes. Otherwise, they're great for cutting clay; as a reinforcing wrap around wood, to help stabilize & prevent splitting; making mobiles; lashing tripods together; holding the car trunk lid down, when carrying a bigger than trunk Suze load...

Occasionally I see ads asking for guitar strings for making jewellery, so it's a widespread idea.

Mine go into my metal recycling bin. It's very stiff wire, so it's hard to reuse.

But they languish in the bin for a while, and sometimes I fish out a piece. Their stiffness makes them good for poking and scraping in the nooks and crannies of small equipment I'm troubleshooting. They are also good when I need a very tough, thin shim, such as when realigning the blade and anvil of old, abused pruning shears.