These docs are for an old release.
Info on upgrading to v4
renderEvent
Renders a new event on the calendar.
.fullCalendar( ‘renderEvent’, event [, stick ] )
event must be an Event Object with a title and start at the very least.
Normally, the event will disappear once the calendar refetches its event sources (example: when prev/next is clicked). However, specifying stick as true will cause the event to be permanently fixed to the calendar.
View a live demo of renderEvent.