It's a calendar. It's a file folder. It's a File-it! The File-it is your complete calendar file system.
Collect documents during the month in the individual file folders, and then tear off at the end of the month using the perforated edges. Use the fold over tab to secure contents for easy filing in any standard-size file cabinet.
The "Notes" section on the back of each folder summarizes contents and finalizes the transformation from calendar to file system.