It seems Google is trying to make it difficult to sync Google calendar and outlook when they discontinued their Google calendar sync.
However there are still install files around in the wild and the sync still works so if you get it installed it all still works - for now.
Download link:
http://google-calendar-sync.en.softonic.com/download
Source link:
http://www.ablebits.com/office-addins-blog/2013/11/20/sync-google-calendar-with-outlook/#google-apps-sync
Also if it doesn't seem to like two stage authentication - instead setup an app specific password instead and it works fine!
Happy syncing!
