A Huge Collection of Spreadsheets for Teachers [What Excel Can Do]
Link: Collection of Excel Spreadsheets for Teachers - Examples & teaching aids - FREE Download | Chandoo.org - Learn Microsoft Excel Online)
Spreadsheet download link: The Excel Workbook for Teachers [this file is 9MB, so you may need to give it sometime to download]
There are so many valuable tricks, ideas and powerful concepts buried in his workbook. I encourage everyone to play with his file (you need to enable macros) so that you can learn a thing or two. If you are a teacher, feel free to use the files to make your classroom teaching even more awesome.