There is a CMS widget that can group events by tag. Each tag will show up as a separate tab on the widget.
Here is an example:
To add tags, head to Admin Menu -> My Lists and select Calendar Tags.
Add in the name of the tag, and the order in which it should appear on the widget.
Then you can edit an individual event in admin menu -> Events. You'll see the option to choose the tag(s)
Edit a CMS page, and then edit a section. Select Insert Widget from the bottom right of the toolbar.
Then you will see the option to add an events widget grouped by tags.
You'll be able to choose which tags to include on the widget.
You can also add a whole calendar to a tag at once. To do that, head to admin menu -> My Lists -> Calendars, and edit a calendar. You'll see the option to add a tag.
Then anything categorized in that calendar will automatically have the calendar tag(s) selected.