php the chain of responsibility design pattern

i was learning design patterns. Now i understand the concept of chain of responsibility design pattern. i know how to implement it , but i could not find any useful resource of a practical examples.
All the examples were just about the code
I could not find a practical usage where i can implement this is real life application. I want to know in what kind of senarios this pattern is most likely to be used..

Any one can help describing a real life Solution using this pattern