You can grab the script Rename Artboards.jsx from gist.github.com because it’s simply one file and I didn’t feel like making an official repository for it.
I started by looking for a solution. This was my first result: How (to) batch rename artboards in Adobe illustrator?
I assumed Illustrator would have some sort of floating script palette, but no… So then I found: How to keep Illustrator Scripts handy?
This seems pretty handy, so the next time I need to automate some task in Illustrator I’ll have to dig in and see if it can be solved with a script.