Recently we posted a simple script to toggle "Hide extensions for known file types" option in Windows:
Create Simple Script to Show / Hide File Extensions in Windows XP, Vista and 7
And now we'll tell you how to add an option "Show / Hide File Extensions" in Desktop and Explorer context menu (menu which appears when you right-click) to make the task faster and easier.
Add “Show / Hide File Extensions†Option in Desktop and Explorer Context Menu under Windows XP, Vista and 7 - Tweaking with Vishal
Create Simple Script to Show / Hide File Extensions in Windows XP, Vista and 7
And now we'll tell you how to add an option "Show / Hide File Extensions" in Desktop and Explorer context menu (menu which appears when you right-click) to make the task faster and easier.
Add “Show / Hide File Extensions†Option in Desktop and Explorer Context Menu under Windows XP, Vista and 7 - Tweaking with Vishal