If you are using Google Calendar, there are two independent systems corresponding to GMail and Google Apps for Domains. The add button at the bottom of the calendar will only work for GMail addresses (this is a Google bug that we cannot fix). However, the following instructions will work properly for all Google-supported mail addresses.

1. Right click on this link and copy the link address:
2. Open your Google Calendar.
3. Click on the Add button in the Other Calendars section on the left, and choose Add by URL.
4. Paste in the iCalendar URL and click the Add button.

If you are using a different calendar system, see the about page.