So Easy... Let's Add Another
Wow that WAS easy! You can add multiple calendars, just click Add by URL again:
Again, here are the two calendar feeds:
WHS Calendar
http://www.google.com/calendar/feeds/2c054n5ehkqcqih12ijes69hl8@group.calendar.google.com/public/basic
WHS Sports Calendar
http://www.google.com/calendar/feeds/p4tppap404hpjd23hvd6m7i7i0@group.calendar.google.com/public/basic
Check it out... I have added two different public calendars: