--- a/rollbot.py	Thu May 19 21:08:43 2016 +0800
+++ b/rollbot.py	Sun May 22 21:48:18 2016 +0800
@@ -56,6 +56,31 @@
             return '(%s) = %d' % (' + '.join('%d' % r for r in rolls), total)
 
 
+class Flip(Command):
+    name = 'flip'
+
+    def usage(self):
+        return '%s or %s <1st-option>[ or] <2nd-option>' % (self.name, self.name)
+
+    def respond(self, words, message):
+        if len(words) == 1:
+            option = self.flip(('heads', 'tails'))
+        elif len(words) == 3:
+            option = self.flip(words[1:])
+        elif len(words) == 4 and words[2].lower() == 'or':
+            option = self.flip((words[1], words[3]))
+        else:
+            return '%s usage: %s' % (self.name, self.usage())
+
+        return self.format(option)
+
+    def flip(self, options):
+        return random.choice(options)
+
+    def format(self, option):
+        return option
+
+
 class Help(Command):
     name = 'help'
 
@@ -86,6 +111,7 @@
 
         self.commands = {}
         self.add_command(Roll)
+        self.add_command(Flip)
         self.add_command(Help)
 
         self.add_event_handler('session_start', self.start)