Events including (Appointments, Reminders, & Tasks) are automatically added to your calendar so you'll never miss an event but you can also easily hide events that you don't wish to view.
1. Click the Mail Drop-down menu in the top left corner, select Calendar from the menu. The Calendar will open to the monthly view by default. The are several view types.
2. Under "My calendars," uncheck the Event you wish to hide. Events with an empty checkbox next to them are already hidden.
Note: To reveal events, simply place a checkmark back to left of the calendar you wish to view.