Rejoice! A PEAR class for Danish numbers is now in alpha: Docs For Class Validate_DK are sparse, but you can see the four methods:

* carReg
* phoneNumber
* postalCode
* ssn

I like this. One person, in this case Jesper Veggerby Hansen, can make a significant contribution to the Open Source world. [An article](http://asay.blogspot.com/2005/09/analyst-nature-and-size-of-open-source.html) I read yesterday told the real story: most projects involve few minds. If you are able to add something (a fine bug report or a piece of documentation), you are golden.

Cheers to Jesper for this micro-project.