The Los Angeles Ruby Study group is interested in visualizing what happens in Rack middleware stacks. Eventually we would love to figure out how to inspect an arbitrary Rack stack - perhaps even follow requests and responses on the fly. But for the moment, we are just trying to build a static visualization of the middleware stack in an out-of-the-box Rails 4 application as documented in this ROR Guide: http://guides.rubyonrails.org/rails_on_rack.html#internal-middleware-stack

This project uses Raphael JS to build animated graphics of different request/response cycles.