git remote add user git@github.com:theirusername/reponame.git
git checkout theirusername/theirbranch
git remote add user git@github.com:theirusername/reponame.git
git fetch theirusername
git checkout -b mynamefortheirbranch theirusername/theirbranch
git remote add user git@github.com:theirusername/reponame.git
git checkout theirusername/theirbranch
git remote add user git@github.com:theirusername/reponame.git
git fetch theirusername
git checkout -b mynamefortheirbranch theirusername/theirbranch