One of the problems I faced integrating Google Calendar with Joomla! was getting a weeks worth of upcoming events from all different calendars to show up on a module.  The third party extensions were bulky and did not give the results I was looking for.  So, I made my own using the RSS feed from Google, Yahoo Pipes and the Simple RSS Reader from JoomlaWorks. These directions are for US East time zones.  To use a different time zone, you will need to change the Google calendar URL code as well as some of the pipe information.

Working with Pipes I've published the pipes here.  To use it, go into your Google calendar, then the calendar details section.  Click on the XML button for the events you want to share.  If you want to share all events, then use the button in the private address section.  If you want to share only the public events, then use the calendar address.  Copy the pipe and edit it for your use by pasting in the XML URL into the URL section at the top of the pipe, then past the following after /basic: ?orderby=starttime&max-results=20&singleevents=true&sortorder=ascending&futureevents=true&ctz=America/New_York Continue this for all the calendars you want to display.  For West Hill, I have 7 calendars.  Now, save, run the pipe, and verify the results.  Once your results are good, copy the URL from the "Get as RSS" icon. Getting it in Joomla! Download and install the Simple RSS Reader from JoomlaWorks.  Put it in the module position you want, name it "Upcoming Events", paste the RSS feed from your Yahoo Pipe, activate it and (optional) enable cache.  That's it.  Your Google calendar is now publishing your upcoming events automatically.