In order to reduce the number of calendars we need to maintain and keep synchronized, we have started to use our Meetup.com calendar as the primary source of event information. The calendars displayed on our Home and Calendars page are still Google calendars, but they draw their data from Meetup.
A quirk of this setup is that the calendars on corbamtb.com only display upcoming events. To see past events, it will be necessary to visit the Meetup calendar.
Another side effect, discovered after the new calendar was implemented, is that people who display the CORBA calendar on their website will need to update it to display the new calendar instead.