Open source programming tool on the rise: Rhomobile Rhodes
Ruby may be the second most popular language on Github, but that won't do you any good if you want to program for the iPhone, a platform that prefers Objective-C, the way God intended when he first created the NeXT machine.
Rhomobile Rhodes is an open source platform for bundling up Ruby websites and stuffing them into an iPhone app. You can even use jQuery Mobile to handle the layout if you wish. It's like building a Web app, but you have to remember that the user has big fat fingers instead of a much more precise mouse pointer.