I’ve released a plugin I wrote for my own blog a while ago to the public. It’s based on the original version by Justin Blanton, but I changed around the HTML output to be more semantic and tidy and essentially rewrote the PHP code. Thus the name — Smarter Archives.
You can see it in action on my archives page. It’s the one at the very top. I originally started using it as a viable alternative to the Extended Live Archives plugin which was broken for me and seems to have been discontinued. I plan to have a version for Habari up soon (as soon as I can figure out how to port it), as you can see from my new projects page.
Update: Smarter Archives is licensed under the APL 2.0.