I have some free time on my hands and I was thinking about learning a new language. I do not plan to use it in my day-to-day job, but I rather want to expand my way of thinking to get a better sense where the dev world is heading from a language perspective and to don't get stuck in my way when programming by rather try new approaches.

I was thinking either a functional language, like Haskell or F# (which is a bit more 'pragmatic from a .NET dev standpoint) or something dynamic (like Python, that in my oppinion has nicer syntax than Ruby).

What can you recommend that is enjoyable, at least a bit practical, but most of all, new (from a c# dev perspective).

I appreciate any answers.