You can also simply click on one of the links above and the OSX calendar application will ask if you want to import the specific calendar.
Sync with your iPhone or iPod Touch (OS 3.0 or greater)
Open Settings.
Select Mail, Contacts, Calendars.
Select Add an Account and then Other.
Finally, select Add Subscribed Calendar.
Type the following address into the dialog box and select Save:
Tacoma Program Center Activity Calendar
http://www.google.com/calendar/ical/nuudpvo2564n0n6sm7coj9use8%40group.calendar.google.com/public/basic.ics
or http://tiny.cc/TacomaCal
Field Trips & Irish Cabin Property Events Calendar