Recommendation for Object-Oriented systems to study

[Ankush Thakur]

Hello,

I'm a self-taught programmer who has managed to claw his way out of Python basics and even covered the intermediate parts. But I feel I have a ton of theory in my head and would like to see some smallish applications in action. More specifically, I'm looking for Object Oriented designs that will help me cement my knowledge and expose me to best practices that books never cover. I have half a mind to start reading up the Django or Pandas source code, but I don't want to overwhelm myself. 

Can somebody recommend smaller and simpler projects I can learn from? And if I can pick the brains of the creator, bonus points!

Thanks in advance!

Ankush