With excitement I read Google’s calendar will now support CalDAV. Yeah, now I can sync Lightening (Thunderbird’s Sunbird plugin) with Google, right?  Nope. I can’t. It only works on Apple’s iCal.  From Google help pages:
“While other calendar applications support CalDAV (including Mozilla Sunbird), Google Calendar only supports CalDAV using iCal.”
Bummer.
UPDATE: I have found a solution, another problem and a solution to that problem.
Lightning: It’s a Sunbird plug-in for Thunderbird.
https://addons.mozilla.org/en-US/thunderbird/addon/2313
Provider for Google Calendar
https://addons.mozilla.org/en-US/thunderbird/addon/4631
I have installed Thunderbird and Lightning from Ubuntu repos (via Synaptic).  But couldn’t get Provider to work or allow me to add a new calendar.  Finally I found a post in a forum that helped.  The issue is you are missing libstdc++ 5.  Install that from Synaptic and you are good to go. 
This is a hit and run how to.  It assumes you know all of the terms used and you have installed add-ons in thunderbird and from Synaptic before.  But if you haven’t and need more detail on how to do anything, please feel free to ask.