Every Rubyist is aware of Minero Aoki's ever useful setup.rb script. It's how most of us used to install our ruby programs before RubyGems came along. And it's still mighty useful in certain scenarios, not the least of which is the job of the distribution package managers. Setup converts setup.rb into a stand-alone application. No longer will you need distribute setup.rb with you Ruby packages. Just instruct your users to use Setup.