MakeUseOf posted a tutorial about installing Ubuntu Touch Preview on your Nexus Android Device

Ubuntu is developing on a touch-focused interface for smartphones and tablets, with plans to ship Ubuntu smartphones in 2014. If you?re interested in trying it right now, there's good news: You can install the preview release of Ubuntu Touch on a Nexus device (the Galaxy Nexus, Nexus 4, Nexus 7, or Nexus 10). Be aware though that this is an early version of Ubuntu Touch. It's been called beta, but it's actually alpha.

  How To Install The Ubuntu Touch Preview On Your Nexus Android Device