Admin is an awesome Django builtin app to create nice CRUDs for your models, and offers a lot of customizations hooks. You can personalize the templates, perform custom filters, modify newly created objects and if that's not enough, you can always create your own view to do something it doesn't by default.

Given the dynamic nature of Python you can do many things in runtime, like add methods dynamically to an object or class. This is particularly useful when writing unit tests.