Copy the code below into your Outlook VBA module (Alt+F11). Connect to a macro button on the ribbon if you use it regularly.

' =======================================================================
' Routine to export selected calendar to a spreadsheet (Date, Subject, Location)
' =======================================================================
Public Sub ExportCurrentFolderToSpreadsheet()
Set myOLApp = CreateObject("Outlook.Application")
Set myOlExp = myOLApp.ActiveExplorer
Set myOlSel = myOlExp.CurrentFolder
Set fs = CreateObject("Scripting.FileSystemObject")
Set a = fs.CreateTextFile("c:\temp\calendar.csv", True)

' Headers
a.WriteLine "Start,Subject,Location"

' Look through each item that is selected
For Each obj In myOlSel.Items
If obj.Class = 26 Then 'appointments
a.WriteLine obj.Start & ",""" & obj.Subject & """,""" & obj.Location & """"
End If
Next obj

' Load excel to view comma seperated values file
'Shell "C:\Program Files\Microsoft Office\Office\excel.exe c:\temp\calendar.csv", vbMaximizedFocus ' Office 2003 on Windex XP
Shell "C:\Program Files (x86)\Microsoft Office\Office14\excel.exe c:\temp\calendar.csv", vbMaximizedFocus 'Office 2010 on windows 7
End Sub