Seems like Ruby on Rails is becoming a popular programming language these days, in fact, it’s overcoming Python books right now! (ok, so I don’t like Python anyway but still…)
You can catch the news at O’Reilly radar here.

While I was looking at the data, though, I noticed something perhaps more newsworthy: in the same period, Ruby book sales surpassed Python book sales for the first time. Python is up 20% vs. the same period last year, but Ruby is up 1552%! (Perl is down 3%.)

Groovy, in the meantime you can try Ruby.