Hello,
I happened to hear about this project from Luis Villa's blog:
http://tieguy.org/blog/2008/09/17/what-these-guys-need-is-a-trademark-license/
I thought I'd write in case you didn't see his post and offer some
pointers about the "Community Mark" concept that he linked to in lieu
of your use of Creative Commons in your license:
http://www.parkingday.org/src/NPD_license.pdf
The problem with using Creative Commons in this case is that you're
trying to apply conditions to using your mark -- rather than condition
the use of a creative work in derivative work -- using concepts from
copyright, rather than trademark.
Now, I'm not a lawyer, but I think Luis has a point in proposing the
use of a the community mark concept (an idea that I made up, I admit).
You can read about where the idea came from on my blog:
http://factoryjoe.com/blog/2006/01/14/the-case-for-community-marks/
http://factoryjoe.com/blog/2006/05/29/why-barcamp-is-a-community-mark/
http://factoryjoe.com/blog/2006/06/01/blowing-up-trademarks/
http://factoryjoe.com/blog/2007/01/18/trademark-in-its-final-throes/
http://factoryjoe.com/blog/2007/01/25/the-burning-man-trademark-controversy/
Basically the idea is that you actually want people to re-use your
mark, but not have to necessarily ask you for permission, or to
establish some explicit licensing arrangement in advance of using the
mark. You quite clearly delimit the demands on reuse of the mark in
your existing license, but to the best of my knowledge, Creative
Commons and copyright really aren't going to help you there -- worse,
you have a registered trademark, which binds you to enforce use of the
mark -- which is at odds with your desire to spread Park(ing) Day.
Anyway, I just thought I'd pass along these links to give you an
alternative perspective on trademark. I don't know that if you found
people violating your mark that you'd necessarily want to take legal
action to inhibit their use of your mark, so going with a community
mark, in some ways, lets enforcement fall to the community of
Park(ing) Day enthusiasts.
Cheers -- like what you guys are doing!
Chris (resident of San Francisco)