Here's how you can install the ImmUnity theme to your Ubuntu computer.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each.
cd /tmp wget http://gnome-look.org/CONTENT/content-files/150278-Immunity.tar.gz
sudo mv /usr/share/themes/Ambiance /usr/share/themes/Ambiance.old
sudo tar xvfz 150278-Immunity.tar.gz -C /usr/share/themes
For more, see the original article at the link below.
ImmUnity: Unity compatible Ubuntu theme | Fresh Tutorial