This screenlet for GNOME and XFCE desktop environments displays upcoming events using the Google Calendar. For notifications the notification library of Python is used.
I wrote this back in 2010 when there were no other screenlets for the Google Calendar. With the uprising of Android and accessibility of the calendar via Thunderbird's Lightning extension I abandoned this project.
At the moment I am quite satisfied with the screenlet. There are some issues of the screenlet daemon reading from the GNOME keyring, but this is a different story. The only thing missing I can think of are error/warning messages.
This screenlet is available in version 1.0 (beta) for download at gnome-look.org and right here.