The Django framework uses decorators to a great extent. An example is the View decorator. Django's View decorators can be used for [j.mp/djangodec]:
Restricting access to views based on the HTTP request
Controlling the caching behavior on specific views
Controlling compression on a per-view basis
Controlling caching based on specific HTTP request headers
The Grok framework also uses decorators for achieving different goals such as [j.mp/grokdeco]:
Registering a function as an event subscriber
Protecting a method with a specific permission
Implementing the Adapter pattern