Ubuntu Font Family

Download ubuntu-font-family-0.70.1.zip from http://font.ubuntu.com/ .
Unzip :   unzip ubuntu-font-family-0.70.1.zip
Archive:  ubuntu-font-family-0.70.1.zip
   creating: ubuntu-font-family-0.70.1/
  inflating: ubuntu-font-family-0.70.1/LICENCE-FAQ.txt 
  inflating: ubuntu-font-family-0.70.1/Ubuntu-R.ttf 
  inflating: ubuntu-font-family-0.70.1/Ubuntu-I.ttf 
  inflating: ubuntu-font-family-0.70.1/copyright.txt 
  inflating: ubuntu-font-family-0.70.1/README.txt 
  inflating: ubuntu-font-family-0.70.1/TRADEMARKS.txt 
  inflating: ubuntu-font-family-0.70.1/Ubuntu-B.ttf 
  inflating: ubuntu-font-family-0.70.1/LICENCE.txt 
  inflating: ubuntu-font-family-0.70.1/CONTRIBUTING.txt 
  inflating: ubuntu-font-family-0.70.1/FONTLOG.txt 
  inflating: ubuntu-font-family-0.70.1/Ubuntu-BI.ttf 

Move the .ttf files to ~/.fonts . Enjoy...