As a member of the Bioruby mailing list, my first post was where is the Bioruby documentation?
Why it is that Bioruby is not well documented? This question pops up so often in the mailing list that I am going to list a couple of resources here:
The best place to get started is at the Bioruby new website. For some reason the other website is still active.
An excellent tutorial written by Katayama Toshiaki among others is available here. Sample scripts on common tasks for sequence manipulations can be accessed from here.
Some Bioruby presentations can be downloaded from here as well.
The following blogs are dedicated in a way to Bioruby and bioinformatics
If you have a specific question post it on the mailing list. And you may have an opportunity to have your question or problem solved by the experts!