Ruby is an "Easy Object-Oriented Scripting Language" that is just emerging in the mainstream.  It is well suited to a wide variety of tasks including system administration, rapid prototyping, Web development, complex text processing using regular expressions, artificial intelligence, and the teaching of object-oriented principles.  Ruby combines the better characteristics of the most popular interpreted languages, but with a refreshingly minimalistic and intuitive feel.

Some of Ruby's strengths:

• Regular, orderly language design
• Automatic memory management and garbage collection
• Perl-like pattern matching features
• OO design from the ground up, not awkwardly grafted on
• Direct access to system calls
• Support for graphical applications through the Tk, Gtk, and FOX toolkits
• Simple, high-level threading support

Ruby is freely available under the GNU general public license.

Resources

• Download
• Tutorial: "Ruby User's Guide"
  • online version
  • tar/gzip for download
• Language reference
  
• Library reference
• FAQ
• "37 reasons"
• Ruby/Gtk installation help
  (note: badly out of date)
• Ruby homepage

Book Support Material
(SAMS Teach Yourself Ruby in 21 Days)

• Numbered source listings
• Misprint list