diff --git a/src/OAuth2/demo.php b/src/OAuth2/demo.php
new file mode 100644
index 0000000..e14be93
--- /dev/null
+++ b/src/OAuth2/demo.php
@@ -0,0 +1,64 @@
+<?php
+require('client.php');
+require('GrantType/IGrantType.php');
+require('GrantType/AuthorizationCode.php');
+
+const CLIENT_ID     = 'your client id';
+const CLIENT_SECRET = 'your client secret';
+
+const REDIRECT_URI           = 'http://url/of/this.php';
+const AUTHORIZATION_ENDPOINT = 'https://alchemy1.nationbuilder.com//oauth/authorize';
+const TOKEN_ENDPOINT         = 'https://alchemy1.nationbuilder.com/oauth/access_token';
+
+$client = new OAuth2\Client(CLIENT_ID, CLIENT_SECRET);
+if (!isset($_GET['code']))
+{
+    $auth_url = $client->getAuthenticationUrl(AUTHORIZATION_ENDPOINT, REDIRECT_URI);
+    header('Location: ' . $auth_url);
+    die('Redirect');
+}
+else
+{
+    $params = array('code' => $_GET['code'], 'redirect_uri' => REDIRECT_URI);
+    $response = $client->getAccessToken(TOKEN_ENDPOINT, 'authorization_code', $params);
+    parse_str($response['result'], $info);
+    $client->setAccessToken($info['access_token']);
+    $response = $client->fetch('https://alchemy1.nationbuilder.com/me');
+    var_dump($response, $response['result']);
+}
+namespace OAuth2\GrantType;
+
+/**
+ * MyCustomGrantType Grant Type 
+ */
+class MyCustomGrantType implements IGrantType
+{
+    /**
+     * Defines the Grant Type
+     * 
+     * @var string  Defaults to 'my_custom_grant_type'. 
+     */
+    const GRANT_TYPE = 'my_custom_grant_type';
+
+    /**
+     * Adds a specific Handling of the parameters
+     * 
+     * @return array of Specific parameters to be sent.
+     * @param  mixed  $parameters the parameters array (passed by reference)
+     */
+    public function validateParameters(&$parameters)
+    {
+        if (!isset($parameters['first_mandatory_parameter']))
+        {
+            throw new \Exception('The \'first_mandatory_parameter\' parameter must be defined for the Password grant type');
+        }
+        elseif (!isset($parameters['second_mandatory_parameter']))
+        {
+            throw new \Exception('The \'seconde_mandatory_parameter\' parameter must be defined for the Password grant type');
+        }
+    }
+}
+
+call the OAuth client getAccessToken with the grantType you defined in the GRANT_TYPE constant, As following : 
+$response = $client->getAccessToken(TOKEN_ENDPOINT, 'my_custom_grant_type', $params);
+?>