git clone https://github.com/paulirish/dotfiles.git && cd dotfiles && ./bootstrap.sh
cd; curl -#L https://github.com/paulirish/dotfiles/tarball/master | tar -xzv --strip-components 1 --exclude={README.md,bootstrap.sh}
To update later on, just run that command again.
When setting up a new Mac, you may want to set some sensible OS X defaults:
./.osx
Suggestions/improvements welcome back upstream!