How do I create object definitions that I can reach from within CI?

[eluser]Starovich[/eluser]
[quote author="Edmundas Kondrašovas" date="1299439339"]Can you specify what exactly are you trying to accomplish?[/quote]

I need to be able to create custom objects inside my controllers and libraries, like I specified in the first post. the "Dog" class is an example, what I really need to do isn't really in the scope of the question.

I just want to know how people do to use objects (OOP) inside their CodeIgniter projects.