Hi,
 I'm announcing Hirb, a mini view framework for console applications,
designed with irb in mind.  It allows you to create table views, tree
views:
  Numeric
  |-- Float
  |-- Integer
  |   |-- Bignum
  |   `-- Fixnum
  |-- Date::Infinity
  `-- Rational

and more.

I've written two tutorials on it:  http://tagaholic.me/2009/03/13/hirb-irb-on-the-good-stuff.html
and
 http://tagaholic.me/2009/03/18/ruby-class-trees-rails-plugin-trees-with-hirb.html.
It's also got some decent documentation: http://tagaholic.me/hirb/doc/.

You can install it with: gem install cldwalker-hirb --source
http://gems.github.com

Enjoy!
Gabriel