gistfile1.rb

# CONTROLLER

# Recent comments on theaters
comments = Comment.find(:all, :conditions => "entity_type = 'Theater'", :order => "id DESC", :select => "entity_id", :limit => 100)
comments = comments.map{ |i| i.entity_id }.uniq
theaters = Theater.find(:all, :conditions => "id IN (#{comments.join(',')})")
@theaters_with_comments = theaters.sort_by{|e| comments.index(e.id)}

# VIEW

%h2 Recent comments
%ul
  - @theaters_with_comments[0..9].each do |theater|
    %li= link_to theater.name, theater_path(theater)