Blogger and remote-control enthusiast Tim Matheson, who previously showed us how to shut down Windows using a text message, posts a script and easy-to-follow guide for doing the same on a Mac. Everything needed for the hack comes included with OS X Leopard, except the cell phone, of course. Matheson suggests setting up a "super-secret" email address that you only use for shutdown messages, but there are other ways of remote-controlling a Mac using keywords. Hit the link to download a safe shutdown script, and post your own remote-control computing tricks in the comments.