Savant is a powerful but lightweight PEAR-compliant template system for PHP. It is non-compiling, and uses PHP itself as its template language so you don't need to learn a new markup system. It has an object-oriented system of template plugins and output filters, so it sports almost all of the power of Smarty with almost none of the overhead.
The Text_Wiki package allows you to transform text structured using Wiki rules into any defined target output format. For example, you can convert Tavi-style Wiki text into XHTML, original C2-style Wiki text into XML, MeatBall style Wiki text into LaTeX, or any other Wiki markup rules into any other format (provided it's programmed properly).
Yawiki is a powerful Wiki system for collaborative document generation. It supports both anonymous and authenticated users. It uses an AreaMap page to generate a hierarchy of pages and navigational elements. It supports page-level access control lists. There is an optional comment system built-in, as well as RSS feeds for individual public pages.
Yawp is a single-file rapid application development framework foundation for PHP and PEAR. When you "include 'Yawp.php'" and call "Yawp::start()", you get: a single easy-to-edit config file for your application, automated authentication processing, and automatic creation of common objects (a database abstraction layer, disk cache, composite logger, benchmark timer, and variable dumper). It provides safe accessor methods for GET, POST, and configuration values. It is fully documented with examples.