Some organizations use the calendar to coordinate RSVP's for an activity that does not count towards their volunteer hours. The most common example is using the calendar to organize something like a chapter meeting for a club. Volunteers need to RSVP so the coordinator knows who is attending, but the volunteer does not receive credit for attending the meeting.
To set this up, you can create a new event or edit an existing one. Under the section "How do you want volunteer to log hours for this event?", you will select "Don't encourage volunteers to log their hours for this event". This will disable the automated notification reminding volunteers to log their hours.
Next, scroll down to the section for "Other Settings". For the question, "Do you want volunteers to associate hours to this event?", select "No". This will prevent the event from appearing as an option if they log associated event hours in the future.