simple example of a form without a model backend

form.html.erb

<%= form_tag('/sample') do |f| %>
  <div class="field">
    <%= label_tag :var1 %><br />
    <%= text_field_tag :var1 %>
  </div>
  <div class="field">
    <%= label_tag :var2 %><br />
    <%= text_field_tag :var2 %>
  </div>
  <div class="actions">
    <%= submit_tag %>
  </div>
<% end %>

routes.rb

post "/sample" => "sample#sample"

sample.html.erb

<%= @var3 %>

sample_controller.rb

  def sample    
    #note to be cautious about checking what
    #kind of input is coming in
    var1 = params[:var1]
    var2 = params[:var2]
    @var3 = var1 + var2    
  end