Jeremy Gibbons explains categories, focusing on them as an organizing principle helpful in managing generic libraries.
Crista Lopes writes a program in multiple styles -monolithic/OOP/continuations/relational/Pub-Sub/Monads/AOP/Map-reduce- showing the value of using more than a style in large scale systems.
Chris Houser and Jonathan Claggett compare macros with monads, suggesting when it is better to use each of them, and pondering what could be done to improve them.
Dustin Getz shows writing monads code explaining how they work and why they are useful.
Carin Meier tells the story of Alice discovering Monads, meeting three types of monads – Identity, Maybe, State-, and learning how to implement them in Clojure.