Credit goes to this url for this post. I repost in case his site goes down and the info is lost. http://www.mikesimonds.com/adding-event-calendar-t111.html
The object to update or insert a new calendar event is the "Event" object in salesforce
There are 4 required fields that need to be inserted in order for the event to be added to your instance of Salesforce.
Start (date and time)
End (date and time)
Those API field names are