I'm a recent git convert. It's great to be able to use git-svn to keep my branches locally without disturbing the svn server. There was a bug that existed in the latest version of the code. I wanted to establish a time when it worked so that I could use git bisect. I couldn't find the right command to move back in time. Thanks.
git checkout HEAD~1
This will move your current HEAD to one revision earlier.
git checkout <sha>
This will move your current HEAD to the given revision. Use git log or gitk to find the revision you’re looking for.