I don't know anything about Ruby, but it's interesting to see typical "enterprisey" patterns appear for people using these scripting frameworks for web-app development. One thing I've always been curious about when evaluating Python frameworks, or looking at Ruby on Rails sample code in Github was how apps look when they start getting large. I usually see a mess, and it sort of turned me off. It's nice to know that some of the same patterns are being though of and applied in these worlds, too.

Also some good comments below on not just jumping into using all these patterns on smaller projects. Take the benefit of being light and nimble starting, then start breaking things apart as the app and teams grow. Best of both worlds.