Support for open government data is an emerging national trend. In January of this year, the City of Austin unveiled its data portal at http://data.austintexas.gov. On February 21, Code for America sponsored "Code Across America", a national day of "hacking" on civic-minded software applications. (That's "hacking" in the original creative sense, not the popular mischief-making sense.)
As part of the event, here in Austin, about 50 people participated in a CfA Hack-a-Thon. People organized around three projects. You can find out more about the projects at the event wiki page.
I worked on the "Find It" team, which focused more on an R&D effort than a target application. The question we set out to answer is could we acquire sufficient datasets from the government, primarily the City of Austin, and what could we do with them once they were incorporated into a common database form? You can read more about that effort at the aforementioned wiki page.
By the end of the day, I had a small Ruby script that would take a location (latitude/longitude) and search for a number of nearby features -- such as libraries and post offices -- and report the closest. After the event, I built out the proof-of-concept prototype into a web-based application that would attempt to determine your current location (using a built-in GPS if your device had one and you permitted it), and display the features on a map.
The result was the Find It Nearby application. You can try the application here: http://nearby.webatx.us/