This can't be done if by the term "global" you mean within all applications for many obvious reasons. The only solutions have been posted.
If you're referring to "global" in terms of Windows Explorer than the link to the "Simplest way to add a command to Explorer's Shell menu" post is the way to start.
Personally I would do this in vbscript to get/format the date then use the autoit com object for accessing the clipboard. Then I'd add into the Explorer context menu using Fast Explorer.