A menu item linkiing to /calendar takes you to opportunities in a calendar format.  Date and Time Specific Opportunities are posted to the calendar by the day they occur.

1. Clicking on the + here reveals filters that can allow you to search for specific opportunities on the calendar.  If none are chosen - ALL date and time specific opportunities appear on the calendar below.  The calendar color-codes Volunteer Opportunities (eligible for service hours) and trainings and other activities such as volunteer recognition events, seminars, socials, etc  (activities that are not counted as service hours) that you want volunteers to be able to sign up or express interest in.
2. The header of the calendar allows you to select between month, week, or day views of the calendar.  The left and right arrows allow you to move forward or backward to the next month, week, or day.
3. The main body of the calendar lists date and time specific opportunities.  Hovering over an opportunity name produces a pop-up with more details on that opportunity.  Clicking on the link for any opportunity will take you to opportunity detail page where you can sign up or express interest.
4. If there are more opportunities than can fit in the grid for that day, a +Xmore link is shown.  Clicking on this will pop-up the day view for that day.

Special Events like days of service, holidays, etc. appear in their own color (as specified by the legend).  Clicking on the name of a special event will take you to a listing of all the opportunities that take place as part of that larger event.  (There are no special events on this image of the calendar)

clicking on 'X more" pops up the day view showing all opportunities for the day.  Hovering over any opportunity shows additional about the opportunity in a pop-up.   Click on any opportunity name to go to the opportunity detail page.

Each filter can be dropped down to expose a picklist of values.  

Additional Filters are initially hidden, but can be exposed by clicking on the "Additional Filters" link.

Clicking on the Search button will then filter the calendar by the choices made.

Search Parameters can be saved for the Calendar Page in the same way they can be saved on the search opportunity page.   The URL for a filtered calendar can be used as a navigation item to create custom calendars.  (Example:  You could create a calendar filtered URL to create a calendar that only shows opportunities for partners,  or only for one specific partner.)