Making Ruby DSLs is incredibly simple... here's a small example.

dsl_example.rb

#################################################################
# The DSL

class DSL
  attr_reader :props

  def initialize(&block)
    @props = {}
    @handlers = {}

    instance_eval &block
  end

  def set(name, value)
    @props[name] = value
  end

  def on(event, &block)
    @handlers[event] ||= []
    @handlers[event] << block
  end

  def handle_event(name)
    if blocks = @handlers[name]
      blocks.each { |block| instance_eval &block }
    end
  end
end

#################################################################
# Let's define our domain!

dsl = DSL.new do
  set :donkeys, 5
  set :hamsters, 99999999

  on :face_plant do
    puts "EIUUGGGHHHHHHH!!!!!!"
  end
  
  on :hamster_died do
    puts "NOOOOOOOOOOOO! HAMMY!"
    props[:hamsters] -= 1
  end
end

#################################################################
# Super sophisticated tests

puts dsl.props
dsl.handle_event :face_plant
dsl.handle_event :hamster_died
puts dsl.props

dsl_output.txt

{:donkeys=>5, :hamsters=>99999999}
EIUUGGGHHHHHHH!!!!!!
NOOOOOOOOOOOO! HAMMY!
{:donkeys=>5, :hamsters=>99999998}