Please recommend a small open source project with the goal of learning PHP on the example of "how it make great uncles". Quality code (to your taste), OOP (possibly) small volume (Drupal, WP and other monsters do not offer), a living community. That would be implemented: the sharing of access, working with databases, caching with PHP (optional), what other typical tasks. If there is documentation for developers — all fine. One more wish is likely unattainable: that would be consistent with recent changes to the language, that is what the code was PHP 5.3.
Thank you in advance, comrades. Let the Force be with you.