I have just released metric_abc. It is a tool that can help you find bad code in your Ruby 1.9 projects. It is much simplier cousin of Flog, but does the job in absence of Flog in Ruby 1.9 world. Check out post on my company's blog as well.
AmberBit team members have posted new tutorial and example code, that will let you integrate Flash Video (FLV) pseudostreaming, which is compatible with Lighttpd/Ngnix module solutions into your Ruby applications. Example is using Sinatra and Rack::Evil, but it's easy to port it to Rails.