So you're new to Ubuntu Linux. You just got it installed for the first time, but you are wondering how to enable DVD Playback, Flash capability, MP3, Quicktime, and other popular media formats. Never fear, here's a command to get it all up and running.
Open up a terminal window and type:
sudo apt-get install ubuntu-restricted-extras
You will be prompted for your administrative password, at which point it will begin to download all the required codecs, making your Ubuntu multimedia ready.