history channel on foursquare

What kinds of information (historical or otherwise) can your library share with visitors/users through location-based networks like Foursquare and Gowalla?

The History Channel is on Foursquare, promoting their series America The Story of Us by putting tips on particular historical locations that include history trivia about the location. It got me to think about how libraries, or at least local collections, could do something similar with tidbits from their archives.

There have already been some examples of libraries inserting references to their digital collections on Wikipedia, and this is an opportunity to add some enhancement and self-promotion to a social media network that seems almost designed for this sort of thing. What kinds of information (historical or otherwise) can your library share with visitors/users through location-based networks like Foursquare and Gowalla?