OpenStreetMap.org is the wikipedia of maps. A free open-licensed geo-data gathering system overseen by the not-for-profit OpenStreetMap foundation.
The project originated here in London, and the servers are still based here. It's a massive worldwide project. All the development is open source, but we need more coordinated development effort, particularly on the website, API and other core components. We'd love more smart developers to get involved.
This weekend will be a development / design / brainstorming session, but it is open for anyone come along and find out more about OpenStreetMap development.
Official Website: http://wiki.openstreetmap.org/wiki/Hack_weekend_May_2010
Added by Harry Wood on March 30, 2010