From the "git tricks I learned from work" department:

git push . HEAD:<branch-name>

This will push your current HEAD to a local branch named . You can also force an update using +, just like when you're using push to update an actual remote. HEAD can of course be a more complicated refspec.

You probably don't use git in as crazy ways as my work does, but knowing that you can use a dot to refer to your local repository in commands like push can sure come in handy every once in a while, especially when doing complicated rebases.