Ask HN: What open source projects should be mirrored?

Hello HN, I'm working on a little side project to mirror open source projects on the web. Nothing major at the moment, perhaps a server on the east and west coast of the US to start with. It just seems like something we need as a way of supporting open source regardless of the services people choose to use like github, bitbucket or google code. What open source projects do you believe should be mirrored and why?