Let's "git checkout" any pull request.

gistfile1.txt

porkrevenge(~/build/fpm) % git branch -a
* master
  remotes/origin/HEAD -> origin/master
  remotes/origin/master

porkrevenge(~/build/fpm) % tail -2 ~/.gitconfig 
[remote "origin"]
  fetch = +refs/pull/*/head:refs/remotes/origin/pull/*


porkrevenge(~/build/fpm) % git fetch
remote: Counting objects: 613, done.
remote: Compressing objects: 100% (386/386), done.
remote: Total 447 (delta 215), reused 261 (delta 61)
Receiving objects: 100% (447/447), 90.98 KiB | 0 bytes/s, done.
Resolving deltas: 100% (215/215), completed with 56 local objects.
From github.com:jordansissel/fpm
 * [new ref]         refs/pull/1/head -> origin/pull/1
 * [new ref]         refs/pull/10/head -> origin/pull/10
 * [new ref]         refs/pull/100/head -> origin/pull/100
 * [new ref]         refs/pull/101/head -> origin/pull/101
 * [new ref]         refs/pull/102/head -> origin/pull/102
 * [new ref]         refs/pull/106/head -> origin/pull/106
....... lots of pull request heads getting fetched.....

porkrevenge(~/build/fpm) % git checkout pull/585
Switched to a new branch 'pull/585'


# Bam, checked out a pull request as a branch.