diff --git a/src/Prototype.php b/src/Prototype.php
index b79798b..9fc8646 100644
--- a/src/Prototype.php
+++ b/src/Prototype.php
@@ -3,6 +3,7 @@
 class Prototype implements \ArrayAccess
 {
     private $drivers = array();
+    private $events = array();
 
     final public function extend($name, $callable)
     {
@@ -14,17 +15,59 @@ final public function hasDriver($name)
         return isset($this->drivers[$name]);
     }
 
+    final public function on($name, $callable, $weights = 0)
+    {
+        $weights = (int) $weights;
+        $this->events[$name][$weights][] = $callable;
+
+        return $this;
+    }
+
+    private function fetchEvent($name, $timing)
+    {
+        return isset($this->events["{$name}.{$timing}"]) ?
+            $this->events["{$name}.{$timing}"] :
+            array();
+    }
+
+    private function fireEvent($name, $timing, $payload = array())
+    {
+        $events_list = $this->fetchEvent($name, $timing);
+        ! empty($events_list) and krsort($events_list);
+        foreach ($events_list as $events) {
+            foreach ($events as $event) {
+                if (false === $event($payload)) {
+                    return;
+                }
+            }
+        }
+    }
+
     final public function __call($name, $args)
     {
         if ($this->hasDriver($name)) {
+            $payload = $args;
             array_unshift($args, $this);
 
-            return \Rde\call($this->drivers[$name], $args);
+            $this->fireEvent($name, 'before', $payload);
+            $ret = \Rde\call($this->drivers[$name], $args);
+            $this->fireEvent($name, 'after', $payload);
+
+            return $ret;
         }
 
         throw new \BadMethodCallException("沒有安裝[{$name}]處理驅動");
     }
 
+    public function __toString()
+    {
+        if ($this->hasDriver('__toString')) {
+            return $this->__call('__toString', array());
+        }
+
+        return '['.get_called_class().']';
+    }
+
     final public function offsetExists($key)
     {
         return isset($this->drivers[$key]);
diff --git a/tests/PrototypeTest.php b/tests/PrototypeTest.php
index 3ca3588..6ad05aa 100644
--- a/tests/PrototypeTest.php
+++ b/tests/PrototypeTest.php
@@ -70,4 +70,52 @@ public function testException()
 
         $o->getColde();
     }
+
+    public function testEventWeight()
+    {
+        $tester = $this;
+        $o = new Rde\Prototype();
+        $event_cnt = 0;
+
+        // 期望順序: 2
+        $o->on('test.before', function($payload) use($tester, &$event_cnt){
+                ++$event_cnt;
+                $tester->assertEquals(array(99), $payload, '檢查參數傳遞');
+                $tester->assertEquals(2, $event_cnt, '檢查呼叫順序');
+                return 7;
+            }, 7);
+
+        // 期望順序: 3
+        $o->on('test.before', function($payload) use($tester, &$event_cnt){
+                ++$event_cnt;
+                $tester->assertEquals(3, $event_cnt, '檢查呼叫順序');
+            }, 7);
+
+        // 期望順序: 1
+        $o->on('test.before', function($payload) use($tester, &$event_cnt){
+                ++$event_cnt;
+                $tester->assertEquals(1, $event_cnt, '檢查呼叫順序');
+            }, 9);
+
+        $o->extend('test', function($self, $arg){});
+
+        $o->test(99);
+
+        $this->assertEquals(3, $event_cnt, '檢查事件是否全執行');
+    }
+
+    public function testToString()
+    {
+        $o = new Rde\Prototype();
+
+        $this->assertEquals('['.get_class($o).']', (string) $o, '檢查預設轉型(string)');
+
+        $str = 'hello world';
+        $o->extend('__toString', function() use($str){
+            return $str;
+        });
+
+        $this->assertEquals($str, (string) $o, '檢查自訂轉型(string)');
+
+    }
 }