Drukkar is a lightweight blog engine and CMS written in PHP 5 with no external dependencies. It supports Markdown, generates clean and valid HTML, and stores individual posts in XML files. It doesn't use a database.
Kitsune is very simple blogging software written in Perl 5. It is designed with simplicity in mind. There is no admin panel; you add entries by creating new text files.
A 2D platform game with a persistent world.
A search tool for OpenOffice.org files.