in reply to (OT) "Learn one new language every year"? Yeah, right.
So much has already been said here, but I still wanted to throw in my 2 cents.
I agree with you, a year is not enough to really learn a langauge. But that is not to say you cannot still learn a lot from even a few months of light study and experimentation. And I think that is their point, to (at a minimum) expose yourself to something new and try to gain a new perspective from it.
Personally, I have never written an application in Erlang, but I learned a number of very valuable concepts from the langauge which I use regularly in my perl code. I once spent a vacation reading a book on Lucid and I never looked at arrays and parrallellism the same since. I have never written anything more than a toy in LISP, but I tend to mark my growth as a programmer in terms of before LISP and after LISP. I have never written a real-time distributed system in Ada 95, but I learned a lot of very useful stuff by reading a book about it. I can say the same for FORTH, Standard ML, Eiffel and Smalltalk; never used them for real, but learned a lot from reading and fooling around with them.
I also have books (that I got off Ebay for cheap) kicking around about SNOBOL, Fortran, CLU and Algol. I have read/skimmed enough of them to understand some of the basics of what they have to offer. Sure they may not be useful outside of niche uses, but it is interesting to me from a historical perspective to see how languages have evolved. Which in turn helps me to see why some of the languages of today are as they are.
I guess my point really is that you don't need to be the worlds best <insert programming language here> hacker to learn important and valuable concepts which can be applicable in your everyday work. Sometimes it's best to just do it for fun ;-)