The Boston Ruby Group holds an open 'project night' once a month at thoughtbot's office in downtown Boston. There will be experienced rails developers there specifically to help newcomers learn the technology.
If you're in Boston, this is actually a great opportunity. There's no charge.
Links:
The Boston Ruby Group:
July's 'Project Night' - July 3rd at thoughtbot:
I know there are some Ruby Groups near San Francisco that have similar monthly meetings/workshops.
-Kevin Bedell