index.html.erb

<% cache 'recent_pages' do %>
  <% @pages.each do |page| %>
    <%=h page.title %>
    <%# ... %>
  <% end %>
<% end %>

page_sweeper.rb

class PageSweeper < ActionController::Caching::Sweeper
  observe Page

  [:save, :destroy].each do |action|
    class_eval %{
      def after_#{action}(page)
        expire_cache(page)
      end
    }
  end

  protected
    def expire_cache(page)
      expire_fragment 'recent_pages'
    end
  #
end

pages_controller.rb

class HomeController < ApplicationController
  cache_sweeper :page_sweeper, :only => [:create, :update, :destroy]
end