YAJL (Yet Another JSON Library) is a small event-driven (SAX-style) JSON parser written in ANSI C, and a small validating JSON generator. It's highly portable, data representation independent, fast, generates verbose error messages including context of where the error occurs in the input text, can parse JSON data incrementally off a stream, and is tiny.
NaturePHP is a classes wrapper using PHP's autoload to create a non-intrusive, simple, organized, and extensible library system. It is aimed at intermediate and advanced PHP developers, providing a lot of non-intrusive functionality for Web site and application development. Upcoming development will include internal library management and the ability to download/update libraries from the repository.