Important: SMS notifications not available after June 27th
Starting on June 27th, 2015, SMS notifications from Google Calendar will no longer be sent. SMS notifications launched before smartphones were available. Now, in a world with smartphones and notifications, you can get richer, more reliable experiences on your mobile device, even offline.
Shame because I got use to text messages 30mins ahead of a event as a sign I should go. However they are right, notifications especially since I have the Pebble smartwatch are good enough now.