My google calendar suddenly disappeared from ical.

Version 10.8.4...

I don't know what happened. I have used my google calendar on ical for years and a few months ago it disappeared. I have restarted my machine, forced quit ical. I have deleted the cache files, etc. stored in the library and then tried to re-add my google calendar to ical. It says it has been added, but it's not there. "Google" shows up on the left in my list of calendars, however it's just the grayed-out title, and there is no calendar beneath it. It syncs to my iphone and ipad without any problems. Any ideas?