Google Calendar has some cool features.. one is that you could create a number of calendars and add what you want to! This way you can segregate stuff by color codes (all events in any one calendar you add on the left take a different color and show that way on the main calendar). So potentially you can have one calendar each for as many organizations that you belong to.. and view all or some as and when you want to… You can have the calendars selected but not view them.. and view them when you want.. and uncheck the box to unclutter the calendar at other times!
Here is one way to bring in the birthdays from other calendars! This post also gives a PERL script to upload multiple events!
The Google Calendar doesn’t have an API (yet), but it does have a hacker’s little friend called import/export. Google accepts two types of calendar formats for import: iCalendar and Outlook’s Comma Separated Values (CSV) export. So if you already have calendar data in Outlook or iCal you can simply import/export at will. (Yahoo! Calendar also exports to the Outlook CSV format, so switching is fairly painless.)