Two weeks ago I visited Scala Days 2015, in Amsterdam. The conference was great, with a lot of high level content.
Sessions I visited. I've attempted to order them by what I found most interesting, but the order certainly not conclusive. All sessions can be viewed online at Parleys:

  1. Types vs Tests : An Epic Battle?
  2. Options in Futures, how to unsuck them
  3. Towards Browser and Server Utopia with Scala.JS: an example using CRDTs
  4. Function-Passing Style, A New Model for Asynchronous and Distributed Programming
  5. Essential Scala: Six Core Principles for Learning Scala
  6. A purely functional approach to building large applications
  7. Functional Data Validation (or How to Think Functionally)
  8. Meerkat parsers: a general parser combinator library for real programming languages
  9. Yoyak : Static analysis framework for Scala
  10. Scala Puzzlers: "In the Matrix, anything is possible!"
  11. Life Beyond the Illusion of Present
  12. Project Valhalla: Part 2 – Value Types in the JVM
  13. The Future of AI in Scala, and on the JVM

I'll write more on what I've learned soon. For now, if you want to know something specific, just contact me.