Elixir
It's just a gut feeling, but I think Elixir could be one of the next big things in technology. It's build on top of battle-proven technology (Erlang) by people with Ruby spirit (Rails-core-committer Jose Valim started it and the project is sponsored by Platformatec). I'm pretty certain that Rubyists will love Elixir .... eventually.
Programming with Erlang/Elixir is quite different though to traditional programming. It has definitely its learning curve.
I will give a sneek-peak intro to Elixir and depending on how much time we've got, I will also try to share a bit of our experience with Elixir at XING. We've got a small Elixir application running in production for 3 months now. Getting it there was more challenging than we initially thought :-)