Bobo Ratio is a one-to-one Web traffic trading script. It trades unique links with a one-to-one ratio. It uses the filesystem to store its data, so no database (i.e. MySQL) is needed. It is modular and easy to set up and use. It is simple. People send you traffic and you can track that and choose to send it back.
dm.KittenAuth implements a CAPTCHA validation solution using groups of images and associated questions. It can generate a form to let a user pick images for one or more groups of images stored in a MySQL database. The user must pick the right images according to the questions associated to the group of images being presented.
SVNBot is a program written in PHP that constantly runs in the background (or foreground, if desired) and monitors your SVN repository (or part of it). When it notices the repository has changed, it notifies everyone on its jabber contact list providing a quick overview of what has been changed (in a format similar to the 'svn log -v' command).
Simple error handler class can be use to intercept and log PHP execution errors. The class provides an error handler function that outputs a stack back-trace with the functions, arguments, file, and lines of where an error occurs, as well the values of super-global variables $_GET, $_POST, and $_FILES, and also the IP address of the current user accessing the site. When used with a MySQL class that triggers PHP errors on a MySQL error, you can use it as a means to debug broken MySQL queries.