I recently updated My Two Cents. My Two Cents (or MTC) is a simple PHP class to add comments to any PHP driven site. It is was written with simplicity in mind but still has some strong features and is easily tweakable.
It consists of a single PHP file and can be added with just a few lines of code.
MTC comes with a CAPTCHA mechanism and a blacklist feature to fight comment spam. The new release adds audible CAPTCHAs as described in Joining .WAVs with PHP. I also tweaked the way Gravatars are used to make additions like MonsterID easier to add.
International users will be happy to hear that all string now can be easily changed through a single language array.
To see the script in action just have a look at the comment form below. It's powered by MTC. Detailed usage infos are available in the manual.
Update I since then switched to Disqus.