Can I install Ruby and Ruby on Rails on an Android? Aware that this is a bit mental, but can I install Ruby on a Galaxy S4 running Jelly Bean 4.2? A console where I can install gems, rake routes and run the Rails server, and browse to my application by putting 0.0.0.0.3000 into Chrome?

Would be excellent for testing little ideas and concepts I have while on the go!

Aware that Android isn't UNIX, but good God if they can install it on Windows, they can install it anywhere!
this can be done


Compile Ruby and Nodejs for android 
Install on device and configure with c/c++ ide (You can use C4droid,CCTools,Terminal IDE.... for installing the expansion modules on с/с++)  
Install rails ($gem install rails)


example:
  
(Click image to enlarge)