Niall Burkley wants to give this talk
Replacing ActiveRecord callbacks with Pub/Sub
As your application grows ActiveRecord callbacks can easily get out of hand - creating a chain of dependencies between your models and mixing in business logic where it doesn't belong.
On some recent projects, I've been using the wisper gem to replace some callbacks with a simple publish/subscribe pattern decoupling callbacks from models.
I'd like talk about the benefits of using this approach and give a brief run through of how to go about it.