From the Wt website at http://www.webtoolkit.eu/wt

"Wt (pronounced 'witty') is a C++ library and application server for developing
and deploying web applications. It is not a 'framework', which enforces a way of
programming, but a library.

The API is widget-centric, and inspired by existing C++ Graphical User Interface
(GUI) APIs. To the developer, it offers complete abstraction of any web-specific
implementation details, including event handling and graphics support"

The Wt::Ruby bindings provide the same widget based api for Ruby programmers. It
is based on the well proven QtRuby code and could be described as a 'QtRuby for
web programming'.

Here is a simple 'hello world' program that shows how a complete web application
can be coded in a single source file 'hello.rb'.

#!/usr/bin/env ruby
require 'wt'

class HelloApplication < Wt::WApplication
  def initialize(env)
    super(env)
    setTitle("Hello world")
    root.addWidget(Wt::WText.new("Your name, please ? "))
    @nameEdit = Wt::WLineEdit.new(root) do |e|
      e.setFocus
    end
    button = Wt::WPushButton.new("Greet me.", root) do |b|
      b.setMargin(Wt::WLength.new(5), Wt::Left) 
    end
    root.addWidget(Wt::WBreak.new)
    @greeting = Wt::WText.new(root)
    button.clicked.connect(SLOT(self, :greet))
    @nameEdit.enterPressed.connect(SLOT(self, :greet))
  end

  def greet
    @greeting.text = "Hello there, " + @nameEdit.text
  end
end

Wt::WRun(ARGV) do |env|
  HelloApplication.new(env)
end

During development this program can be started from the command line, where it
will run as a self contained web server:

$ ./hello.rb -- --docroot . --http-address localhost --http-port 4000

A release version can be run under Apache2 via the FastGCI interface with
no change to the source.

See the tutorial on the Wt::Ruby wiki for an introduction to the Wt toolkit, 
and programming in ruby:

http://wiki.github.com/rdale/wtruby/tutorial