Here is a guide to install the Dorian Theme by *killhellokitty* on Ubuntu 13.04. You can install the Dorian theme by adding the killhellokitty PPA maintaned by hellokitten.
Dorian-theme ~ A Darkly Elegant Theme. Dorian has many of its own unique characteristics. To name a couple, hovered buttons grow in size, and insensitive buttons/widgets have a diagonal pattern distinguishing them from normal or active states. Dorian’s appearance is consistent between Gtk2 and Gtk3. Gtk2 uses the pixmap-engine** to resemble Gtk3 as closely as possible.Visit the Dorian Theme page on deviantART.
To add the PPA and install the Dorian theme open a terminal window and copy+paste the following lines:
sudo add-apt-repository ppa:killhellokitty/themes.ppa -y
sudo apt-get update && sudo apt-get install dorian-theme -y
When the installation is finished you can close the terminal window and to use the Dorian theme you can change themes using Ubuntu Tweak.
To start Ubuntu Tweak and to make the Dorian theme your default theme follow the steps below.
To start Ubuntu Tweak press the SuperKey and type: ubuntu tweak
Click on the Tweaks button
Click on the Theme button
Click on the Gtk theme button
Select the Dorian theme you like
Click on the Window theme button
Select the Dorian window theme you like
Close Ubuntu Tweak when done