Most of the stuff I write is typically in an imperative programming language; I usually don’t stray much further than, say, shell scripting, Perl, or Ruby. However, I’d love to learn a language that’s just way outside of what I’m comfortable with: one way I could do this is to learn a functional programming language. I’m thinking about starting with Erlang, but Haskell might be a good candidate as well.

I think the Zotonic project might be a great place to start in order to learn Erlang.