Not impressive at all; it's Ruby roots are obvious and it screws up virtually every place where performance matters in JavaScript and the DOM. Definitely an 0.1 attempt. You're better off with SproutCore or Cappuccino. Also, it's not even lightweight!

JavaScript in not Ruby. Good code in Ruby != good code in JavaScript. The author would be far better off contributing to existing JavaScript frameworks than trying to make JavaScript work like Ruby.

Care to elaborate, or are you just making baseless accusations? Is it just classes you object to?

That's super impressive ;)