This seems like a successor of Railscasts, exposing specific gems and walking through the installation and getting up to speed. Both GoRails and Railsscasts seem like a great resource, so all I can say is keep it up!!
The thing I would personally like to see more, is screencasts from (or similar to) Destroy All Software[0]. These don't typically target very specific gems, but rather cover general aspects of programming, design, testing methodologies and how those concepts integrate. I personally found those far more thought-provoking.
Another side-benefit is that whereas some screencasts about a specific gem or a library become almost irrelevant when new versions are released, those more approach-oriented talks and screencasts don't go stale that quickly.