Saw a great Kotlin talk by Hadi Hariri from JetBrains at Javazone this year. [1] What I liked about it was that instead of the usual "this is how you do X in language Y" it focused on the immediate value it could bring to professional developers used to Java. Made me really want to try it out and start using it at my job.

[1]: https://2016.javazone.no/program/kotlin-ready-for-production