ICS files are considered the standard format for sharing calendar information and are used by Google Calendar, Apple's iCal and Mozilla's Sunbird. If you'd like to access and share a calendar's information in spreadsheet form via Microsoft Excel, it's possible to import the original ICS file into Excel as though it was a text document. While you may lose a little bit of formatting in the process, this is a simple solution for most people's conversion needs.
Text Import in Microsoft Excel
Launch Microsoft Excel.
Go to "Fill," "Open" and change the "Files of Type" drop-down field to "All Files (.)."
Double-click on the ICS file you wish to convert into an XLS. The Text Import Wizard will appear.
Click the "Delimited" radio button in the "Original data type" box, then click "Next."
Check the "Tab" box in the "Delimiters" section, then click "Next."
Highlight the column(s) containing dates and click the "MDY" radio button to format them as dates (optional).
Go to "File" "Save As" and choose "Excel Workbook (*.xls)" from the "Save as Type" drop-down field, then click "Save."
Excel Calendar ICS Import Macro
Download and install the Excel Calendar Import Macro (see Resources). As of early 2010, this macro costs $25.
Highlight "Import From ICS File" in the "Select Task" box.
Click "Browse" next to "File to Import" and double-click on your ICS file.
Click "Do It" to start the import process.
The Excel Calendar Import Macro really just speeds up the formatting process. If you don't mind doing the work yourself, follow the directions in Section 1 and make any necessary formatting changes at the end.