When you want your objects to refer to / have associations with other objects, it can quickly become a complex procedure. Ryan Daigle to the rescue! Ryan has built Roxy, a "Ruby Proxy-Object Library." He's also put together an awesome blog post with the motivation for developing Roxy and some code examples showing how it works. Roxy gives you the ability to add some rather ActiveRecord-esque functionality to your classes and their instances.

Straight from the horse's mouth: