Add to .bash_profile to automatically activate a virtualenv matching the directory you cd into

.bash_profile

function cd {
    builtin cd "$@"
    dirname=${PWD##*/}
    if [ $dirname ] ; then
    	venv="/var/www/virtualenvs/"${dirname}
    	if [ -d $venv ] ; then
        	source ${venv}/bin/activate
    	fi
    fi
}