PIMF (Php Is My Framework) is a micro framework for PHP that emphasises minimalism and simplicity. It is based on proven design patterns and a fast object relational mapping mechanism, and is designed to be easily updated without having to rewrite your projects. It includes mechanisms for easily coupling controllers to ExtJs and Dojo.
Analog PHP is a short and simple logging package for PHP 5.3+ based around the idea of using closures for configurability and extensibility. It functions as a static class, but you can completely control the handling of log messages through closures (aka anonymous functions), and it also comes with a dozen pre-written handlers. It is well-documented, with examples for each type of log handler, and ultra-concise. The core is literally only 43 lines of clear, non-obfuscated code, and the whole is only a fraction of the size of comparable packages (for example, 293 total lines vs 1021 for Monolog).
Spoon is a PHP5 library that focuses on speed, both in page execution and coding agility. Because of its clear and logical structure, it offers a very small learning curve for both the experienced and not-so-experienced developer. Spoon provides a well documented library with a large collection of classes that you can use while building Web applications.