This 'Thing' was easy, in that I already use Google Calendar. (You can see from the sea of colour on the screenshot how heavily it is used!) However as I played with, following through the instructions, and tried to find out "how to..." for a fellow Cam23 participant I did make some discoveries. Thanks to Cam23 therefore I have an even better set-up than before.
For me the ability to share calendars is where Google Calendars comes into its own. My family seem to lead busy lives - and it makes it so much easier when planning to be able to see all events at a glance. I can see that in a library setting this would also come into its own - though i suspect there might be a period of 'playing' before all had sorted out exactly what went on the calendar and how to share (i.e. which events in one's calendar are personal and therefore of no interest to those you share with and those you need them to know)