Blitz templates is a fast PHP template engine written in C and compiled as a PHP extension. It started as a php_templates replacement, but developed into much more. It is based on extensible template controllers (custom view classes in PHP) and weakly-active templates (simple logic in HTML). Benchmarks show that it is one of the fastest template engines for PHP, even though it's not trivial and makes Web application closer to a smart MVC-like architecture model with maximal separation of HTML from your code. It was designed for big high-load Internet projects with a lot of complex presentation logic.
Drivel is a GNOME client for working with online journals, also known as weblogs or simply blogs. It retains a simple and elegant design while providing many powerful features, including support for LiveJournal, Blogger, MovableType, Advogato, and Atom journals. (Systems based off these are also supported, including WordPress and Drupal.)