Just a quick tip, this one!
If you have a model that is polymorphic, say a comment model:
class Comment belongs_to :user belongs_to :commentable, :polymorphic => true end
and you want to link to the item the comment relates to in the admin system, you can do this:
<%= link_to comment.commentable.title, [:admin, comment.commentable] %>
Note this assumes all of your commentable models have a title attribute or method, and that you have used normal RESTful routes. The :admin symbol will namespace the link to /admin
