Monkey-patching really? You're forgetting what else Rails has in our ecosystem: Github.

1.) Fork a project on Github, say the push notification gem https://github.com/jpoz/APNS

2.) Alter behavior in your branch https://github.com/jamesdaniels/APNS

3.) Optional bit, send a pull-request with your changes

4.) Vendor it or require your fork in the Gemfile: gem 'apns', :git => 'git@github.com:jamesdaniels/APNS.git'

Tada!