davidbody/ajax_controller.rb

## ajax_controller.rb
class AjaxController < ApplicationController
  def handle_checkbox
    render :text => "You entered: #{params[:my_input]}"
  end
end

## index.html
<!DOCTYPE html>
<html>
  <head>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
    <script type="text/javascript">
      $(function() {
        $('#my_checkbox').click(function() {
          var checkbox = $(this);
          checkbox.attr("disabled", true);

          $.ajax($("form").attr("action"), {
            type: "POST",
            data: $("form").serialize(),

            success: function(data) {
              $('#output').append('<p>Received from server: ' + data + '</p>');
            },

            error: function() {
              alert("Oops, something didn't work!");
            },

            complete: function() {
              checkbox.attr("disabled", false);
            }
          });
        });
      });
    </script>
  </head>
  <body>
    <div id="page">
      <form action="handle_checkbox">
        <p><label for="my_input">Type something and click the checkbox</label> <input id="my_input" name="my_input" type="input"/></p>
        <p><label for="my_checkbox">Checkbox</label> <input id="my_checkbox" name="my_checkbox" type="checkbox"/></p>
      </form>
    </div>
    <div id="output"></div>
  </body>
</html>

## routes.rb
AjaxCheckbox::Application.routes.draw do
  post "handle_checkbox" => 'ajax#handle_checkbox'
end
	class AjaxController < ApplicationController
	def handle_checkbox
	render :text => "You entered: #{params[:my_input]}"
	end
	end
	<!DOCTYPE html>
	<html>
	<head>
	<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
	<script type="text/javascript">
	$(function() {
	$('#my_checkbox').click(function() {
	var checkbox = $(this);
	checkbox.attr("disabled", true);

	$.ajax($("form").attr("action"), {
	type: "POST",
	data: $("form").serialize(),

	success: function(data) {
	$('#output').append('<p>Received from server: ' + data + '</p>');
	},

	error: function() {
	alert("Oops, something didn't work!");
	},

	complete: function() {
	checkbox.attr("disabled", false);
	}
	});
	});
	});
	</script>
	</head>
	<body>
	<div id="page">
	<form action="handle_checkbox">
	<p><label for="my_input">Type something and click the checkbox</label> <input id="my_input" name="my_input" type="input"/></p>
	<p><label for="my_checkbox">Checkbox</label> <input id="my_checkbox" name="my_checkbox" type="checkbox"/></p>
	</form>
	</div>
	<div id="output"></div>
	</body>
	</html>
	AjaxCheckbox::Application.routes.draw do
	post "handle_checkbox" => 'ajax#handle_checkbox'
	end