I just updated my MacBook Pro to Mountain Lion and set up iCal to sync my Google calendars using CalDAV. I also have iCloud set up between my iPad and MacBook Pro to sync calendar, mail, etc. My MacBook is now showing all of the desired google calendars as well as allowing me to edit google calendars in the iCal app which are appearing online on the Google Calendar - that part is working great! I set up my iPad in a similar way, but it is only showing my basic single google calendar. I have set up a shared Gmail account on my iPad and set up an Exchange account that I tried to use specifically for the calendar......still not showing other calendars. I have tried a lot of the older suggestions on this topic, mostly written in 2010/2011 and some things have changed in Google and iOS since then so I thought I would try to get some updated suggestions.