Wayne Seguin explains the ideas behind the Ruby Version Manager (RVM) and the problems it solves, as well as the SM shell scripting framework.
Orion Henry explains what make Heroku's PaaS tick, in particular the new extensible Cedar stack as well as Doozer, the implementation of the Paxos algorithm created at Heroku.
Aaron Patterson talks about performance in Ruby and Rails, some of the challenges Rails and Rack pose for the Ruby GC, and much more.
Justin Sheehy and Damien Katz discuss Riak and CouchDB, the strengths and trade-offs of different approaches to NoSQL, and why both databases are written in Erlang.
Rich Kilmer talks about the benefits of using Ruby and Rails at LivingSocial and the state of the Ruby community and Ruby in the enterprise.
Kostis Sagons talks about how type checking can help with a dynamic language like Erlang and how static analysis tools like Dialyzer or automated refactoring tools like Tidier help keep code clean.
Gregory Brown explains the Ruby Mendicant University, a free online school for software developers that combines mentoring and training.
Bob Ippolito talks about building web services with the Erlang-based MochiWeb and the differences to the Yaws web server, the strengths of Erlang and Python, and more.
Ville Tuulos talks about Disco, the Map/Reduce framework for Python and Erlang, real-world data mining with Python, the advantages of Erlang for distributed and fault tolerant software, and more.
Gregory Collins talks about Snap, a high performance web framework for Haskell, where it fits in the web framework spectrum, the Iteratee I/O model, Haskell performance and much more.
Francesco Cesarini and Simon Thompson discuss how Erlang's design allows fault tolerance and resilience, modular error handling, details of the actor model implementation and distributed programming.