[eluser]Unknown[/eluser]
First off, let me just say that I admire the simplicity of your menu library. I noticed that the current active menu item is derived from the current controller, which only worked for me after removing an extra slash from the strripos() function inside your _check_current() method.
As an aside, it would be nice to include code to determine if the active menu item is a method of the current controller. As it is, your menu library would wrap its current_tag around all menu entries which are methods of the active controller.