Everything is in the title...
I'm behind a corporate proxy and cannot access the IntelliJ sources with the git protocol.
I have access to git repos with http though, but jetbrains one is not configured to allow such access.
$ git clone http://git.jetbrains.org/idea/community.git idea
Initialized empty Git repository in C:/Documents and Settings/gphilip/idea/.git/
fatal: http://git.jetbrains.org/idea/community.git/info/refs not found: did you run git update-server-info on the server