I haven't ever had to monkey patch Rails before but recently I was implementing localisation of select prompts. I started building a method like this in my application_helper.rb.
Nothing wrong with this but as I used it more and more I realized I was passing f.object in as the resource arg every single time. I then understood I should be sending the message to the form builder object. Here's the monkey patched version. Complete correct vowel prefixing.
Object name gives me the correct class name and the indefinitize method sorts out prefixes.
I placed this file in the lib directory and required it in the initializers and everything worked as expected with a much cleaner API for my select_prompt.