Bits By The Pound

From https://help.ubuntu.com/community/RestrictedFormats

Go to Applications → Add/Remove…
Set Show: to All available applications
Search for ubuntu-restricted-extras and install it.

Install VLC. Totem-gstreamer will not work properly with DVDs

You may need to go to
/usr/share/doc/libdvdread3 and run
$ sudo ./install-css.sh

to install the DVD decrypter codec, but i am not sure.

Reboot and then use VLC to play the DVD.