The following Steps are help you to play Video DVD Movies in Your Ubuntu 10.04 Lucid Lynx
Fist You have to add mediubuntu repositories
$ sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list
http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list
$ sudo apt-get --quiet update
Update Key
$ sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring
$ sudo apt-get --quiet update
If you already added mediubuntu repository you can skip above steps
Now install the libdvdcss library.
# sudo su
# apt-get install libdvdcss2
# apt-get install libdvdread4
# cd /usr/share/doc/libdvdread4/
# ./install-css.sh
