gistfile1.rb

# Model

class Donor
 #.... a bunch of stuff

 def self.find_for_params(params={})
  find :all, :order=>sort_statement_for_param(params[:sort])
 end

 def self.sort_statement_for_param(sort)
  case sort 
  when 'first_name'
   "first"
  else
   "created_on"
  end
 end
end

# Controller

class DonorController
  def index
    @donors = Donor.find_for_params(params)
  end
end

# View

<table>
  <tr>
    <th><%= link_to "First name", :sort=>"first_name" %></th>
    <th><%= link_to "First name", :sort=>"last_name" %></th>
  </tr>
  <tr>
   content...
  </tr>