Ask HN: What skill will you try to learn over Christmas break?

Writing and releasing a simple Android application. The release part is really helping me focus on a less hacked together codebase.

Backbone.js. I'm a backend developer but need to get up to speed on the new ways of doing the frontend.

I'll start learning Scala more seriously, most likely with Coursera's help.

this has me fascinated. How are you getting on with it?

I am working on rewriting a PHP application in Rails to learn Rails.

D3 and possibly work more on a haiku generator.