Does CI have a application wide controller?

[eluser]Unknown[/eluser]
I am new to Codeigniter and i was wondering if CI had a controller that was available site wide. Something like Ruby on Rails' application controller. I even think Cakephp has an application controller.

If Codeigniter does not have an application controller, how do i go about making methods available throughout the entire site?

Thanks in advance for any and all information.