This is a screencast in which Paul Engel (of Internetbureau Holder B.V. which was co-organizer of the European RubyAndRails conferences) will demonstrate how to use the Ruby gem StackTracy within a small Sinatra application. It records the application stack tree within a certain period and displays it in a HTML page or in your console. It can also dump the recorded events to a CSV file. You can reduce the stack tree by specifying which classes and modules to trace.
Please note that you can also use StackTracy without Sinatra!