Mediabuntu

To play DVDs we need to install a couple things so that we can decode DVDs. First add the mediabuntu repository then update it:

sudo wget http://www.medibuntu.org/sources.list.d/hardy.list -O /etc/apt/sources.list.d/medibuntu.list
sudo apt-get update && sudo apt-get install medibuntu-keyring && sudo apt-get update

Then install libdvdcss2

sudo apt-get install libdvdcss2

your computer can now play DVDs.