Sked lets you solve the problem of "I have all these calendars and I want to share (some) of them with other people". It lets you take any combination of Google calendars and arbitrary other iCalendar feeds and make new feeds that you can then share with people. You can also only share the "I'm busy" data from a calendar, instead of it's full data if you want.
Once you've given someone one of these new feeds, you can always update their permissions afterwards - this means if you add new calendars, you don't need to tell anyone else. Also, if you gave someone too much/too little access, you can fix that.To begin Login to Google