So I faced the problem of having >5000 spam comments on my blog. To fix the problem I decided to upgrade and add some simple captcha plugin to the site. Unfortunately, and thanks to Fantastico installer, the upgrade process just did not work and left wordpress to partially broken state in the end.
To fix it, I got the crazy idea of rewriting the blog software. Some hours later (now) the blog is up and running again - this time without wordpress. Just a super simple hack made of few hundred lines of php. At least there will not be any spam problem as comments are not supported. Yet.