NSObject.rb

class NSObject
  def method_missing(meth, *args)
    obj_c_meth = meth.split('_').inject([]){ |buffer,e| buffer.push(buffer.empty? ? e : e.capitalize) }.join
    if respond_to?(obj_c_meth)
      send obj_c_meth, *args
    else
      raise NoMethodError.new(meth.to_s) 
    end
  end
end

# In the REPL:
v = UIView.new
# => #<UIView:0xaa45260>
v.background_color = UIColor.white_color
# => #<UICachedDeviceWhiteColor:0xaa41180>
v.backgroundColor
# => <UICachedDeviceWhiteColor:0x967c2e0>
v.asdf
# => #<NoMethodError: asdf>