Calling a controller via cron

[eluser]GeXus[/eluser]
Does anyone know how to call a controller via cron? Since cron requires the path and everything in CI is routed through the index - if I were to call /public_html/system/application/controllers/controller.php that wouldn't work...

Anyone know of workarounds? What needs to be run is pretty tied into CI, otherwise I would just do it outside of it...