Calendar sharing settings
You can share an entire calendar, which is useful when you are part of a group that has shared events, like a softball team. Click on the small triangle next to a calendar's name, then choose "Share this calendar".

Sharing with friends
You control the information that other users can see and with whom your calendar is shared. Calendars can be shared with individuals that you specify.

Share with the world
You can also choose to make your calendars public and searchable by other users.