What I was after
In this case, I was working on a site where my local master branch (Git) had somehow become almost 50 commits behind and I also had some unusual conflicts. Knowing that the remote master branch was current and had all of my previously merged changes already, I was looking for a way to reset my local master branch to match the server side without doing a typical pull request (since I was getting too many weird conflicts).
I ended up asking a friend to remind me of the command since we were chatting. He pointed me to Reset local repository branch to be just like remote repository HEAD (http://stackoverflow.com/questions/1628088/reset-local-repository-branch-to-be-just-like-remote-repository-head).
The important bits
In the end, with the master branch checked out, it was as simple as running two commands:
git fetch origin
git reset --hard origin/master