First step: a black background

ray-pong1.rb

require 'rubygems'
require 'ray'

Ray.game 'Pong', :size => [800, 800] do
  register { add_hook(:quit, method(:exit!)) }

  scene :start do
    # Exit when q is pressed
    on :key_press, key(:q){ exit! }

    render do |win|
    end
  end

  scenes << :start
end