It’s a gathering of citizens in cities around the world to write applications, liberate data, create visualizations and publish analyses using open public data to show support for and encourage the adoption open data policies by the world's local, regional and national governments.
Check out the wiki for more info: http://wiki.opendataday.org/Vancouver2013
When & Where
David is an open data policy nerd, entrepreneur and speaker. He co-wrote the Vancouver Open Data policy back in 2009 that helped Vancouver be one of the first cities in North America doing open data.