Probably the biggest programming language hit of the last year was Go - it was also (according to Tiobe) the fastest growing language in 2009. Year 2008 belonged to Erlang: Amazon started their SimpleDB based on Erlang, and Facebook announced their Erlang powered chat application.
For some time I was wondering if the incoming year can bring another player entering the game, and I came to a conclusion that a good candidate is Io. It's a prototype-based programming language, which is amazing in many aspects: it combines very simple grammar with incredible power, provides an interactive shell and a rich set of libraries out of the box, it also allows hundreds of thousands of concurrent processes through actor based model. Io is surprisingly mature as for a language with so few Internet resources and is definitely worth trying - it has been recommended even by some renowned hackers like _why and Ruby's creator Matsumoto Yukihiro. You can find a few Io example routines here.
Give Io a try if you have a minute, I can guarantee that you won't be sorry.