In a previous post, I have already alluded to the fact that distributed version control systems such as Git and hosts such as Github and the collaborative manner of working which they engender, are having a profound effect on the Open Government movement.
In particular GitHub is developing into one of the major hubs for this as it acts as a mechanism for collaborative work and as a social network.
I would like to explore this further through a collection of links:
GitHub Repositories of Cities
Github Repositories of State Governments
(a) The UK Government (much code and in particular the source code for gov.uk)
(b) The White House (api-standards and code for the petitions website)
Github Repositories of Government Agencies
...and of course, see also Robert McMillan's Wired article on how GitHub helps "hack the government. I will keep expanding this list as I come across more repos. Please feel free to contribute in the comments section.