Martin Fowler's book on DSLs

apparently if you take smalltalk or a lisp dialect, cut the performance by an order of magnitude, remove most of the really interesting metaprogramming features (leaving pretty much just a crass eval function), and all of the awesome interactivity and incremental development functionality that make systems like Squeak and SLIME such a joy to use, and finish by making it vaguely line-oriented, you get a language that makes people go gaga.

go figure.

Wohoo! Someone who gets the idea of a state machine framework. Check out my effort at building one of these - datamagi.org. This is quite interesting actually - if you look through the change history at the top of the page you can see I've been using one of Fowler's books as a reference. Previous to seeing this article I had not known of any prior work in this area.

Yes, ruby is a good tool for DSL.