Site Countdown
This module for Joomla! 2.5 and 3.x is displayed only in the frontend part of the site when logged.
You can configure:
- the percentage of remaining time before showing the warning;
- if hide/show the timer by defaut;
For administrator part download http://extensions.joomla.org/extensions/administration/admin-desk/24793
Special thanks to Denilton Cymbron