phpDays is a flexible PHP 5 framework for rapid Web site development. It features an MVC architecture, Ajax support, YAML configuration, database abstraction (MySQL, PostgreSQL, MS SQL, etc.), a good collection of standard models, an excellent quick start guide, and logging to files or firephp.
Nearforums is a lightweight powerful discussion forum that can be installed within minutes on Linux or Windows servers with MySQL or MS SQL database servers. It includes great features like sign-in with Facebook/Twitter, navigation with tags, full Web administration, built-in search engine, RSS feeds, and accessible HTML. It is SEO friendly.