Sometime you want to add Next or Previous links to your blog posts or whatever model. Its really easy, just add a couple of instance methods to your model

class Post < ActiveRecord::Base
  def next
    Post.where("id > ?", id).limit(1).first
  end

  def prev
    Post.where("id < ?", id).limit(1).first
  end
end

Then just call it like so:

<%= link_to "Next Post", @post.next %>
<%= link_to "Prev Post", @post.prev %>