If you’ve been working on Rails 2.3 engines (the new stuff that comes with Rails 2.3 not the old engine plugin) and you start running into either of these errors:
A copy of ApplicationController has been removed from the module tree but is still active!
Or
can’t dup NilClass
Don’t go find a new job at McDonald’s. Read this article and feel the love again.
In fact if you do any engine or plugin or gem development read that article. It will make you happy again.