Ruby on rails is a fairly new programing language to me and version one was released a little over two years ago and it benefits from the open source community. For more information on ruby check out there website as well as Wikipedia.
The other half of the language involves what is called Rails or Ruby on Rails, and Rails is an open source frame work makes programing a breeze. Imagine adding a database table to your MySQL DB and then having it show up in your website without changing any code! its that smart.
I am in the process of looking for some good books on Ruby. the language its self is almost intimidatingly to simple and requires a bit of Command Prompt to get things rolling but the following links will get you up and running in no time.
Using: http://apacheguide.org/ruby.php
Installing: Installing Ruby on Rails on Windows
Ruby IDE: Radrails
Screencast: Create a blog in 15min