There may be more than one way to ask this question, so here's a desciption of the problem. I was working on master and committed some stuff and then decided I wanted to put that work on hold. I backed up a few commits and then branched from before I started my crap work. Practically this works fine, I just now have a different branch as my main development branch. I'm wondering how I could change things around so I'm working on master again but it doesn't have my junk work and said work is on a different branch.
Some ways this could be asked/solved: How do I rename my master branch to something else and then rename something else to master? How do I back up master and then cause all commits I've backed up past to be on a different branch?
Thanks for all the (quick) answers! They're all good.
In addition to the other comments, you may find the -m (move) switch to git-branch helpful. You could rename your old master to something else, then rename your new branch to master:
git branch -m master crap_work
git branch -m previous_master master