My way of initializing JavaScript unobtrusively

application.html.haml

%html{:lang => "en"}
  %head= render "shared/head"
  %body.app{"data-events" => yield(:body_events)}
    = yield

application.js.coffee

App = window.App = _.extend {Models: {}, Views: {}, Controllers: {}}, Backbone.Events

App.init = ->
  eventNames = $("body").attr("data-events")
  eventNames = if eventNames? then eventNames.split(/\s+/) else []
  App.trigger event for event in eventNames

$ App.init

events.js.coffee

App.bind "signup", ->
  modal = document.getElementById "signup-modal"
  new App.Views.SignupView(el: modal).render()

gistfile1.rb

  def client_initializer(*event_names)
    event_names = event_names.join(" ")
    if content_for?(:body_events)
      content_for(:body_events) << " " << event_names
    else
      content_for :body_events, event_names
    end
    nil
  end

show.html.haml

- client_initializer :signup

-# Rest of view goes here...