A first attempt to integrate Google Calendar into Gnome Shell for those of us who don't use Evolution. At the moment it only consists of a short Python script and a copy of Google's GData Module.
The Python script needs to be running in order to have events from Google in gnome-shell as it implements the dbus interface which is queried.
The script needs to know your email address and a key through which your calendar can be accessed. This key is part of the URL which is used to share your calendar with other people without making it publicly accessible.
Have a look at the 'Calendar details' page in the configuration interface for each of your calendars. It is labeled as a 'Private Address' and looks like this: private-a87abd05h51ecabeuc71316e76348a4d
As I'm new to Gnome development and dbus I want encourage you to fork this. If you have ideas for improvement please go ahead, I'd be happy to read about it.