Monkey patch

A monkey patch is a way for a program to extend or modify supporting system software locally (affecting only the running instance of the program).

Quotes

 * If it walks like a duck and talks like a duck, it’s a duck, right? So if this duck is not giving you the noise that you want, you’ve got to just punch that duck until it returns what you expect.
 * Patrick Ewing on Monkey/Duck patching in RailsConf 2007.