While in the physical world, "ruby" refers to a red gemstone, in the computer world, ruby is an object-oriented programming language. If a special woman in your life asks for a ruby for her birthday, I would recommend choosing the gemstone for the gift.
The Ruby programming language was created by Yukihiro Matsumoto and is named after the birthstone of one his colleagues. Interestingly, the pearl (as in the Perl language) is the June gemstone, while ruby is the July gemstone. This makes the subtle suggestion that Ruby is a step forward from Perl.
Like Perl, Ruby's strength lies in it's simplicity. The syntax is very basic and it is completely object-oriented. This means every type of data handled by the language is treated as an object, even data types as simple as integers. The source code can be interpreted by the official Ruby interpreter or by JRuby, a Java-based interpreter.
Ruby is an open-source language, like PHP, which means it is free to download and use. It can be compiled and run on just about any operating system, including Unix, Windows, and Mac OS X. For more information on Ruby and to download the Ruby software, visit the Ruby Home Page.