No need to add every half day, holiday or PTA event to your calendar one at a time! Just subscribe to the MNS calendar.
For Google Calendar click here.
For iCal, add a new calendar and use this url: https://calendar.google.com/calendar/ical/calendar%40mnspta.org/public/basic.ics. This link will also work for Outlook (just have Outlook open when you click the link.)