Alto CMS is a flexible Web Content Management System with various community features and extensions plugins. It includes the obligatory admin panel, an content editor, blogs, multimedia attachments, an invite system, comments for tracking discussions, and a user mailbox system. It's also PHP based, can use Mysql/Mariadb or Postgres using PDO with bound parameters.
FlatNuke is a Web-CMS and portal script, that doesn't require a relational / SQL database. It uses plain file storage exclusively. It has the common blog, news, forum, download, gallery, and calendaring functionality.
CleverStyle is a lean WebCMS written in PHP. It provides simple content and page management, blogs, comments, cron job hooks and deferred tasks, disqus integration, feedback forms, OAuth2 and hybrid social networking logins, image galleries, Plupload, polls, WYSIWYG editors, and static html pages, IPv6 support, divergent file and database storage, and mirror functionality.
feindura is WebCMS with file-based storage and a lightweight architecture, suitable for small and visually pleasing websites. It's easy to set up, utilizes MooTools for its interface and administration area, CKEditor and provides frontend style editing, fully UTF-8 aware, allows pretty URLs, sitemaps, Open Graph integration, file management, localization, RSS/Atom feeds, has backup functionality, and it's plugin-extendable.
Liferay Portal is a portal software for collaborative enterprise intranets and extranet web sites with application integration. It features a built-in web content management system with theming, custom pages, widgets and common navigation structures. Liferay is implemented as Java servlet but supports portlets in PHP or Ruby. It's available as open source community edition and commercial package.