Teacup is a community-driven DSL for RubyMotion. It has CSS-like styling, and helps create complex and simple layouts in iOS and OS X apps. Teacup aims at making UI develpoment in RubyMotion less tedious. It's like Interface Builder for RubyMotion!
Gemfile gem 'teacup', '~> 3.0.1'
install gem install teacup