I've tinkered with
blosxom and
greymatter.
blosxom is the sleeker and more configurable of the two, but I ran into a few problems that were beyond my competence. The blosxom mailing list was somewhat helpful. I've been wanting to set up something with blosxom on my home machine, but I'm pretty lackadaisical about it.
greymatter is a little more stable and more userfriendly. I got great help from the greymatter forums, but I found that a couple of features I wanted would require visitors to use javascript, which is not what I wanted. It's possible that's no longer the case. There seemed to be a community of people contributing mods and templates, though not to the extent that people contribute to blosxom, which is by design extremely modular.
Both require perl.