Awesome Print

awesome_print is a Ruby tool that provides "pretty printing" support for your objects. It's a bit like p, pp or, if you prefer, puts obj.inspect, but with significantly improved, contextual, colored output. Its creator and maintainer is Michael Dvorkin of Fat Free CRM fame.
Being able to see "inside" Ruby objects on the fly can prove useful whether you're debugging some code your tests did not dare reach or you're just playing around in irb. The most common way to examine objects is with p or the inspect method, but these don't format their output in a particularly easy-to-read way. pp - part of the standard library - is a pretty printer that improves matters but it still leaves a lot to be desired. awesome_print takes it all to the next level.
A visual comparison between pp and awesome_print proves compelling:

awesome_print's most compelling features are showing you the index of array elements within its output, inheritance for the classes of embedded objects, and color coding. Further, it's highly customizable, with the ability to set indent levels as well as the colors for each type of data shown.
To get up and running, gem install awesome_print and then require 'ap' and use ap in place on anywhere you'd usually use p. Yep, that's it.

http://github.com/michaeldv/awesome_print
http://www.rubyinside.com/awesome_print-a-new-pretty-printer-for-your-ruby-objects-3208.html