I have been asked that question and have asked the question myself a couple of times. There are so many different technologies that I can choose to complement my current skill set, why Ruby?
Well, I came across an interview from EngineYard blog recently - Chicks That Rip: Ines Sombra.
Ines’ answer is almost exactly word for word of my own answer to the question:
What attracted me most to the Ruby on Rails community is how bold it is. This community is not afraid to experiment and innovate. What I find especially interesting is the prevalence of polyglot systems and cutting-edge data store solutions. Databases are put to the test in Ruby on Rails, and these applications are defining the future of how systems will be constructed. It’s amazing.The community, the rate of innovation and polyglot systems - this gets the geek in me excited.