.gitconfig

[github]
user = your-username
password = your-password

[alias]
# git pullrequest branch-name "title line" "description blah blah"

pullrequest = !sh -c 'curl -s -u "`git config --get github.user`:`git config --get github.password`" https://api.github.com/repos/`git remote show -n origin | head -n 2 | grep -o github.com[^.]* | cut -b 12-`/pulls -d "\\{\\\"title\\\":\\\"$2\\\",\\\"body\\\":\\\"$3\\\",\\\"head\\\":\\\"$1\\\",\\\"base\\\":\\\"master\\\"\\}"' -


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breaking it down:

sh -c '' -   
  run a shell, reading parameters passed in

git config --get github.x
  get git config variable

git remote show -n origin | head -n 2 | grep -o github.com[^.]* | cut -b 12-
  a very hacky way to get the api path for the repository
  surely there is a better way?

"\\{\\\"title\\\":\\\"$2\\\",\\\"body\\\":\\\"$3\\\",\\\"head\\\":\\\"$1\\\",\\\"base\\\":\\\"master\\\"\\}"

  the json string. i can't think of any way to make the leaning toothpicks (via @vhata) dissappear?