Joomla-Date-Example-Module is a project mainly written in PHP, it's free.
This is a very simple Joomla! module that shows the current Date.
This is the first Joomla! module that I have created! It's very simple but it may help someone to understand the basic structure of a Joomla! module. More information here: http://docs.joomla.org/How_to_create_a_module