Make data from several cities available through GeoData Checkout ( http://mapmeld.github.io/geodata-checkout/ ), an open maps API developed last year by Code for America.
Draw to download data inside your neighborhood, or any custom area on the map. Map data, make timelines, or display in Google Earth.
A lightweight Node.js wrapper around PostGIS or MongoDB. Installs on Heroku in minutes. Data available through GeoJSON, KML, and JSONP APIs.