Packaging Rails Applications for Offline / Third Party Use on OS X
With OS X 10.5 (Leopard), Ruby and Rails are included by default, so deploying Rails applications for use by non-developer third parties is easier than ever before. With this in mind, Jason Crystal has put together a solid guide to packaging a Rails application for offline use on OS X. He uses tar2rubyscript and Platypus to do the packaging. The article also demonstrates how to set up your various Rails application configuration files to cope.
Also of interest are the comments which include links and references to alternative techniques. It's still very incomplete, but one alternative mentioned is RoRGate, an OS X app that bundles up Rails applications with a site specific browser.