I played with Haskell, to the point of being able to read and understand larger chunks of Haskell code - but I haven't written anything of note in it yet. Not sure I ever will, either. I started playing with it due to git-annex (which was written in Haskell, and that triggered the interest) and the LYAH book (which is beyond awesome, by the way). Coming from an OO/imperative background, functional programming seemed interesting, and even though I didn't end up using Haskell, the tricks and ideas I borrowed did have a huge impact on me.

The other language I played a lot with, and ended up using a lot this year is Clojure. The main reason I started learning it is because its not only a LISP, it's a mostly functional, yet, practical language, whose concurrency and paralellism support is unparalelled. Being a JVM language, with great interoperability with Java also means that I can use existing Java libraries. All in all, it had great properties, and a syntax I was already somewhat familiar with (being an Emacs user for the past 12 years or so did expose me to at least some lisp, after all!), so my next few projects, which will likely see the light of day in early 2012, will be written in Clojure.

I also learned a bit about sparc assembly, because I had to, and as much as I didn't want to, I learned to read PHP a little bit better than I used to. I'm not exactly proud of that, but nevertheless, that's what happened.