Ruby is a programming language installer designed by Yukihiro Matsumoto. The idea behind Ruby is to have an object-oriented programming language, similar to Perl and Smalltalk. The program directives, like in Smalltalk, are also smaller than in some other Object Oriented languages, such as Java. Ruby also has an automatic memory management, meaning that, unlike C and C++ memory, this one is handled by the language, not by the programmer.
The language is excellent when trying to create performance-driven, compact applications. There are also some applications based on Ruby, such as Ruby on Rails and Watir, which are popular among developers.
RubyForge has come up with an installer package, so that machine installation of Ruby is quick and easy. The installer package has an API for beginners as well as the "Book of Ruby", which teaches basics of Ruby as well as advance programming. This package is definitely a good place to start if you have a wish to program in Ruby or if you need to use a Ruby-based applications.