DBPrism is an open source framework to generate dynamic XML from a database. It connects Oracle databases with Apache Cocoon, providing a high performance DBGenerator with functionality such as parallel content aggregation and ESI cache protocol. It also includes a powerlful database oriented CMS built on top of Apache Cocoon2 and DBPrism.
Enzyme is an architecture for creating user-searching-user applications. Right now, it is primarily useful as a resume create/search and HR management system. However, it's potential uses are wide-ranging, and it offers PHP developers an alternative to relying on simple "keyword" searching systems.
Tof is a Web-based photo album. It is based on slooze, and additionally has viewing rights, picture rating and sorting by rate, indexing with keywords, picture upload through the Web, thumbnail creation, and multiple languages support. It is being developed with PostgreSQL, but should be easy to port to MySQL thanks to phplib.
XMLDB uses an RDBMS to persist arbitrary XML documents. Due to its storage mechanism, searching for and recalling documents is extremely quick. You can also perform XSL translation on documents with surprising speed. The library can be used in any program to store libxml2 documents. A PHP module is also included, making XMLDB into a complete three-tier Web application development suite.
PostNuke is a Weblog/portal system featuring an extremely easy-to-use Web-based installation script. It is extremely developer and community friendly, with active development progressing, support forums around the world, and live support via its own IRC network. It was originally based on PHP-Nuke, but was rewritten with security and performance in mind.