Make your calendar public
When you choose to make your calendar public, all of your events will appear in the public search results of Google Calendar and Google Web Search. Additionally, other Google Calendar users can view the calendar and its public events by adding it to their calendar list or using your Calendar Address.
If you make your calendar public and select 'Share only my free/busy information (hide details),' your event details won't appear in Google Web Search or Google Calendar search results. Only your free/busy information will be visible to those who access your calendar at its address or add it to their calendar list.