jsGoogSheetGoogCalendarSync

/*
var calId = "zept.ca_5h55iuorjqdujn0vcp458b9f4g@group.calendar.google.com";
var sheetName = 'Events';
*/

function addToCal() {
  var ss = SpreadsheetApp.getActiveSpreadsheet(),
  var sheet = ss.getActiveSheet(),
  var data = sheet.getDataRange().getValues(),
  var calendar = CalendarApp.getCalendarById('zept.ca_5h55iuorjqdujn0vcp458b9f4g@group.calendar.google.com');

  for (var i = 1, ok = 1, len = data.length; i < len; i++)
  {
    var title = (data[i][1] + ': '+ data[i][2]),
        startDate = data[i][4],
        endDate = data[i][5],
        eventID = data[i][8],
        longDescription = ('Description: ' + data[i][2] + ' by ' + data[i][0] + '\nMore info: ' + data[i][7]),
        location = data[i][6],
        dateEvents = CalendarApp.getEventsForDay(startDate); //why does this not work?
    
    for (var j = 0, jlen = dateEvents.length; j < jlen; j++)
    {
      if (dateEvents[j].getTitle() == eventID)
      {
        ok = 0; 
        break; 
      }
    }

    if (ok) //if ok what?
    {
    CalendarApp.createAllDayEvent(title, startDate, {description: longDescription, location: location}) 
                                    //, endDate
      .removeAllReminders();
      ok = 1;
  }
  }
}

//add a menu when the spreadsheet is opened
function onOpen() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet(); 
  var menuEntries = [];  
  menuEntries.push({name: "updateEventCalendar", functionName: "addToCal"}); 
  sheet.addMenu("UpdateCalendar", menuEntries);  
}