What are some well designed Ruby projects suitable for study of coding the Ruby way?

I am starting out on Ruby and have heard that there is a 'Ruby way' of coding. What are some projects, apart from Ruby on Rails, that are开发者_StackOverflow suitable for study and is agreed upon as well designed?

Prawn was explicitly created to be not only a damn good PDF generation library, but also designed from the ground up as an example of well-designed, well-factored, idiomatic Ruby code. Prawn also spawned the Ruby Best Practices book and the RBP Blog.