Save keystrokes and stay DRY with SimplyPresentable:

  <% present(foo).form do |f| %>
    <%= f.text_field :bar %>
  <% end %>

Instead of

  <% form_for(
       foo.new_record? ? {
         :url => 'http://example.com/foos',
         :html => { :method => 'post', :id => 'new_foo', :class => 'new_foo' }
       } :
       {
          :url => "http://example.com/foos/#{foo.id}",
          :html => { :method => 'put', :id => 'foo_1', :class => 'foo' }
        } :
      ) do |f| %>
    <%= f.text_field :bar %>
  <% end %>

SimplyPresentable is a plugin that introduces the idea of presenters to rails:

martinfowler.com/eaaDev/PresentationModel.html

Rails helpers are functional, and organized around controllers, not domain objects. Helper functions that are intended to operate on data types that span controllers end up being in the ApplicationHelper, or packaged into modules and included in other helpers.

SimplyPresentable attempts to fill the OO void left by a functional helper only approach to presentation:

  <%= link_to 'Show Foo', present(@foo).url %>