If you need multiple Google Calendars as well as Exchange Calendaring and perhaps a personal booking system using Windows Live, you’ll be happy to know you can easily sync multiple Google calendars like I do in the colour-coded screenshot.
To add them, just go to m.google.com/sync on your phone. Log into the web page, select your device and toggle the calendars you want to sync. You can sync up to 25 Google calendars onto your Windows Phone. Before leaving the screen, tap and save your settings. I've also bookmarked the page in my Lumia browser.
These newly synced calendars appear whenever your phone syncs with Google’s servers. If you've commanded your phone to save battery power, it's not going to sync your calendars. By default, my Nokia Lumia looks at Google for sync data every half hour. When I set an important appointment on my calendar, I normally sync it before I leave the meeting that set the appointment.
The Windows Sync team at Google also have enabled the Lumia with an ability to search for Gmail messages that haven’t been downloaded to the phone yet. That's also handy. The option to "search more in Google Mail" is found at the bottom of the results list for a local search.
Li Yin -- Sync multiple calendars using advice from the Windows Sync team at Google.