Ruby Meta-Programming Screencasts

The first video (called "Objects and Classes") starts off slowly, but it starts to get interesting once you're about ten minutes in. Dave explains how to define a singleton method on an object, and explains how Ruby resolves a method call. This leads nicely into this conclusion, which you should have no trouble in understanding if you watch the video:

There's no such thing as a class method in Ruby. Instead, all we have are singleton methods that happen to be on class objects. -- Dave Thomas

Episode 2 ("Sharing Behavior") begins with a nice introduction to using prototype based inheritance (as employed by JavaScript), in Ruby.

Note: I clearly published this review before I finished writing it. Sorry about that; the rest of the screencasts are also great, but I haven't had a chance to summarise what I like about them...