Using government data to create citizen-friendly web applications has been a top priority of federal Chief Technology Officer Vivek Kundra.
His former office in the District of Columbia put that philosophy to use during the massive storm President Obama dubboed "Snowmaggedon." The District's Department of Transportation created a Snow Response Reporting System that shows when particular streets were plowed or salted and shows live views from traffic cameras set up all over the city.
It's useful to see the condition of streets on your route to work before leaving the house. I wonder how accurate it is, though, since the animated maps show some streets haven't been plowed or salted at all since the storm's start on Friday.
Still, it's a good example of what local governments can do with the data they collect all day. You can look at specific locations, like the White House or Dupont Circle.