I apologize for boring the vast majority of my readers who do not use PyBlosxom but I’m trying to at least mention each "released" projects here once for the sake of completeness — even if it’s only interesting to a small number of them.
I posted a note a few months ago mentioning a stronger CAPTCHA I had created to deal with blog spam. A few friends pointed out that they were having excellent luck with Akismet which filters using a model similar to some of those old collaborative spam filters.
Building off earlier work, I build an Akismet plugin for PyBlosxom. I’ve gone through a couple of iterations on the PyBlosxom lists and the results have been great. If you use don’t use PyBlosxom, there are plugins for WordPress (where the system originated) and I imagine for other blogging systems as well. Its an effective and attractive alternative to a CAPTCHA.
You can grab my plugin on my PyBlosxom hacks page