Shows current working git branch in you bash prompt.

Git branch bash prompt

function parse_git_branch {
    git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1) /'
}
PS1="\[\e[32m\]\$(parse_git_branch)\[\e[34m\]\h:\W \$ \[\e[m\]"
export PS1

Found in this excellent tutorial for using git by David Winterbottom.