I became a dad last may. Therefore, I am really interested in all the initiatives which aim to teach kids programming. @tonydavids0n and fdearle praised the virtues of Groovy as language to introduce programming concepts thanks to its powerful but concise syntax.
Moreover, this talks targets DSL creation. The creation of you own language (no matter how small it is) is fascinating to me and I guess any developer.
@fdearle is the author of Groovy Domain Specific Languages. When I visited the Packtpub website, the book was at only 5€! So, I bought it. If you visit the book's site and the promotion is no longer running, do not dispare. At the very end of the talk the author shares a 50% off code. Yes, watching the video until the end pays off!
Traits are one of the best Groovy features. Personally, I had not used them a lot until recently. But the more I use them, the more they help me to write cleaner and more reusable code.
Please watch this talk by @cedricchampeau if you want to understand how Traits work.