Ruby has been in ridiculous demand in Chicago for at least a year. I blame Groupon. :) They've hired big chunks of three or four consulting shops and are building their own internal teams.
In Boston, it is absurd for Rails developers also.
It doesn't help call volume-wise that "Quantronix" seems to be outsourcing calls to india and calling about positions in Texas regardless of my stated Boston-only preference.
One of the Obtiva owners (consulting shop) wrote: http://nuts.redsquirrel.com/post/2680658687/chicagos-ruby-de...