Information Manager handles formatting and the links on a Web page automatically. It also generates personalized pages, handles sessions and authentication with the client (Web browser), and can be used to do just about anything that requires the client to log in or get personalized content.
Kilongalonga is a shoutbox application which can be put on a Web page to allow people to leave a short message. Visitors can include a URL with their message. The IP addresses of message posters are tracked within the database. It is customizable to your preferred language, and includes support for English and Kiswahili.
bigquotes is a quotes database based on the bpquotes project, with some minor (for the moment) enhancements. It is designed to let IRC users add funny quotes for others to see. A banning system, Web-configurable options (session support, registration, admins, timeout for voting, etc.), and other facilities are planned.
user-online is a php-script which allows webmasters to include a summary of users online on their websites. It counts the users who have been online since a defined time and shows the total users in a small table, which can be placed anywhere on the website. The contents of the table are sorted by the total users in particular directories.
mod_header_modify can change or remove incoming HTTP headers, and it can also add headers that weren't sent by the client. It can thus be used to manipulate the behaviour of content handlers that you don't want to (or can't) change. Another option might be to simulate various user agents, perhaps in conjuction with mod_rewrite.