EveryBlock Chicago is a mash-up of government information and Google Maps.  I LOVE the way it pulls together public information from disparate city agencies and departments and adds layers of relevance and accessibility.

You can locate crime reports, restaurant inspection scores, property transfers, street closures and even filming schedules. Search by address, zip code or neighborhood and you'll see a map loaded with the locations of each event. EveryBlock also includes business reviews from Yelp and lost and found ads from Craigslist. You can even look at pictures that have been geotagged in Flickr!  It's a really easy way to explore your neighborhood or your city.