Mac OS X options for running a Ruby file in the background repeatedly

Question

I wrote a Ruby script that I want to run in the background repeatedly as long as the computer is running. I was planning on using GeekTool to get this .rb file to run in the background, but I'm having issues seen here using GeekTool to run my script.

The thing is that I want this script to be a complete surprise (it's a message display system for my wife) so I want to be able to have it start running every time her computer starts up and keep running as long as her computer is on. If I can't use GeekTool to do it then I have no idea what to use.

What can I do?

Answer 1

Geektool ended up working out for my needs after all.

Answer 2

You use launchd

Answer 3

Lingon (despite not being actively supported) will help you create a launchd setup, and has quick access to the launchd man pages.