I'm still on the hunt for a replacement for my photo database software (sigh...), which means that occasionally I'm procrastinating by looking for something. The newest direction that I've been going is museum software. Most of that is tailored to run on an Internet server, but that's something that can be done by localhost.
It does look like there's quite a few open source and free cataloguing software solutions for museums - so maybe, with a good bit of luck, one of them will be suitable for my purposes. (For most of the things I've looked at until now, one of the dealbreakers is that everything is uploaded into a new folder structure. I have a system for my files that helps me to find them outside of the database, and I'd very much like to keep that...)
While looking for stuff, I've stumbled across a "tagging game" (in German only, sorry folks) where you can look for, and tag, items in medieval artwork. So in case you need something to do and like to look at (and for) old things, you might want to check out the Austrian ThingTag!