Here are a small “copy-paste-howto”:
sudo wget http://www.medibuntu.org/sources.list.d/`lsb_release -cs`.list --output-document=/etc/apt/sources.list.d/medibuntu.list; sudo apt-get -q update; sudo apt-get --yes -q --allow-unauthenticated install medibuntu-keyring; sudo apt-get -q update && sudo apt-get install -y ubuntu-restricted-extras non-free-codecs w32codecs totem-mozilla libdvdcss2 totem-xine xine-ui libxine1 libxinerama1 libxine1-all-plugins libxine1 libxine1-ffmpeg libdvdnav4 libdmx1 libdvdread4 gstreamer0.10-plugins-bad gstreamer0.10-plugins-ugly vlc smplayer smplayer-themes smplayer-translations && sudo /usr/share/doc/libdvdread4/install-css.sh
Enjoy, and thanks to bucknasty