To create a new calendar, click File > New > Calendar. If the calendar is one you plan to store locally, you need only provide a name and color. If it is a remote calendar, enter the name, color, URL, and a refresh frequency. The refresh frequency determines how often Evolution checks to see if the calendar has changed. If you are working with someone who publishes an online calendar, you might want to check for updates every thirty minutes. On the other hand, if you have displayed a sports team schedule in your calendar, you might not need to refresh it more than once a week.
The icalshare.com Web site has an extensive list of shared online calendars, including national and religious holidays, phases of the moon, sports, and local and regional events.