Never log again to your extranet to see your calendar.
Google calendars that auto-update itelf, wouldn't it be cool ?
Extralendar is a google app script for automatic export of the extranet calendar to google calendar.
See the wiki
Go to the FAQ
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY expressed or implied. Use it at your own risk.
You can only use this program with valid credentials.