Broadly speaking, there are two ways to create a DSL. One is to invent a syntax from scratch, and build an interpreter or compiler. The other is to tailor an existing general-purpose language by adding or changing methods, operators, and default actions. This article explores using the latter method to build a DSL on top of Ruby.

Website: http://www.artima.com/rubycs/articles/ruby_as_dslP.html