From the early days of Windows 3.11, I have been used to having a font viewer application on the operating system I use. So, it is quite surprising to see that Ubuntu does not ship with a font viewer by default!
Thankfully, there are many such applications available in its package repositories and one of them is Font Manager. Installing it is easy:
$ sudo apt-get install font-manager
Open it from the Dash as Font Manager. It displays all the fonts on the system, you can view the character set of each in detail, the languages it supports and details about the font itself.
Tried with: Font Manager 0.5.7 and Ubuntu 12.04 LTS