The example application below is a simple "Hello World" type program. It will simply display the message "Hello World" in a window. Note that there is no shebang line (#!/usr/bin/env ruby) as this is intended to be run from Shoes itself, as is common with Shoes programs.
Shoes.app :width => 200, :height => 140 do para "Hello World!" end
The Shoes.app method call encapsulates the entire Shoes application. The parameters passed to it are the width and height of the window in pixels. Inside are all things you'll see inside of the application window. In this case, a para (or "paragraph") displays the text "Hello World."