Just installed the Release Preview of Windows 8 and I am liking it so far.
However I have run into a problem with the Calendar app. I had no issues with adding my Google account to the Mail/Calendar app. But then looking in the Calendar app only my default Google Calendar shows up.
I have tried going to Google Sync at m.google.com/sync (where you had to go to set up sync of multiple calendars for the Mail app on Windows Phone). Here a device named "WindowsMail" has appeared, however when selecting it I am not able to choose which Calendars to synch to, but only "Enable 'Send Mail As' for this device." and "Enable 'Delete Email as Trash' for this device.".
So it appears that Google Sync is not recognizing "WindowsMail" as a Calendar app, but only as a Mail App. Is there any other way to enable sync of multiple Google Calendars for the Windows 8 Mail app? Or are you at Microsoft working on getting Multiple Calendar sync to Work for Windows 8?
Thanks beforehand for the help.