This is demo gfCalendar plugin form.
gfCalendar will help you to add an event to Google the calendar after sending the form by the user.
For a form insert on the page it is necessary to add shortcode:
[gravityform id="1" title="false" description="true"]
id – number of the form
title – show title
description – show description
After submitting this form you can see new event on shared google calendar.