I'm trying to get a postmarked postcard from every county and county-equivalent in the United States sent to me. It can be sent by anyone, but it has to be postmarked from a zip code within the county. Ideally, I would like the postcard to be about the county it was sent from, but it's not a requirement.
I've set up an separate blog to keep track of all of those postcards, as to not clutter up Dan's excellent blog. You can keep up with it here: http://3141postcards.blogspot.com/
Right now I'm going through and soliciting local Chamber of Commerces and Visitor's Bureaus to see if they will send me one for free. Once I get a P.O. Box, I will allow unsolicited postcards to be sent to me from loyal readers :)