How to Enable Multiverse Repository in Ubuntu

Ubuntu comes by default with Multiverse repositories installed by not enabled.  There are many useful packages in multiverse that won't appear unless you enable the repository.  What is multiverse?  It's basically a repository of software packages not supported by ubuntu proper.  This includes non-free and restricted-use packages.  Don't let that scare you.  For the most part, it just means that you may be using some closed-sourced software.  Many of this software is quite common (e.g. Java).

You can enable this repository simply by selecting the multiverse checkbox under System > Administration  > Software Sources.  You might also want to check universe and restricted while you're in there.  This can also be accomplished via terminal:

sudo gedit /etc/apt/sources.list  (backup first if squeamish)

The # or ## character(s) represent a line that's commented out.  Removing these characters from the beginning of a line will make it live.  Simply find the lines beginning with deb and ending in multiverse and remove the #. 

sudo apt-get update

Finish off with an update, and you're finished!  Multiverse is now enabled.