The following joomla extensions are published here:

Availcal15 joomla 1.5 compatible
Availcal Jommla 1.6 and higher compatible
Article Tips for Joomla 1.6 and higher compatible
GoogleCalendar for Joomla 1.6 and higher compatible

Each extension in its own folder with (if present) subfolders for the component, the module and the plugin.
The installation zip files are in the root of each extension.

For more informatie look at the wiki pages.