I sat on this for awhile because I was hoping to make it better before I 'released' it, but I've come across two major roadblocks: 1) I'm not very good 2) I don't have a lot of time. So I decided I might as well just make it public now.
It's a simple Shoes browser for Librelist. When I started it, it was quite a clever idea as the Librelist Archive Browser was just a list of lists and a calendar. You had to select the list and then guess which days had messages by clicking on the calendar. I modelled this app on that interface, but with the benefit that the calendar indicated which days had messages.
Of course, since then, the Librelist browser has improved greatly (although there is a significant delay/bug in recent messages not appearing) by implementing a threaded style view of archives.
Should I ever a) get clever and/or b) get lots of time, I'd still like to improve this, just for me.