OpenStreetMap.org holds a mapping party at Congressional Cemetery on Sunday, July 15 10 a.m. to 3 pm.

OpenStreetMap (OSM) is a collaborative project to create a free editable map of the world. Two major driving forces behind the establishment and growth of OSM have been restrictions on use or availability of map information across much of the world and the advent of inexpensive portable satellite navigation devices.

I heard about this project at Wikimania 2012 which is going on this week at George Washington University and other venues around town including  Tech@State events.