PHP On Pie is a PHP framework that combines the best ideas from PHP projects like Drupal, CodeIgniter, Kohana, and ZendFramework. It has very few core concepts: classes, models, events, slots, and tools. It lets you repackage completed apps into plugins that you or others can use later. Its smart database classes allow you to implement vertical and horizontal partitioning (sharding) easily to handle millions of users.
CubicWeb is a semantic Web application framework that empowers developers to build Web applications by reusing components (called cubes) and following the well known object-oriented design principles. Its main features are: an engine driven by the explicit data model of the application; a query language, RQL, similar to W3C’s SPARQL; a selection+view mechanism for semi-automatic XHTML/XML/JSON/text generation; a library of reusable components (data model and views) that fulfill common needs; the power and flexibility of the Python programming language; and the reliability of SQL databases, LDAP directories, Subversion, and Mercurial for storage backends.