The Ruby meetup in SF is huge. There are also smaller more elite Ruby groups in SF if you can find them. Out there it seems there is a large need for good Ruby talent, so if your good you just need to get the word out in the Ruby community.
Boulder has the Bouler.me ( http://boulder.me ) going on but I think it just ended. Otherwise there is a Boulder Ruby meetup and the Boulder New TechMeetup both of which would be great places to look. I will keep an ear open for Rails specific work in Boulder.
I am looking to relocate in the next month and I want to get into Rails development (as in, for money as opposed to a hobby).
If you or anyone can give advice (particularly about these two attractive locales), shoot me a note at jraines@gmail.com