Ajaxian has just posted a summary of Prototype 1.6

This is big. Prototype 1.6 is a major upgrade, and the first RC has been released. There is a large number of updates and my pet favourites are:

* The event system has been cleaned up. It now works the way you would expect, with “this” doing the right thing
* You can observe and fire custom events on the DOM (a la Dojo)
* Thanks to the custom events, DOMContentLoaded is normalized across browsers via: document.observe(”contentloaded”, function() { … })
* AOP-lite: Simple interception and function currying
* Function delay and defer: (function() { $(”form”).fire(”requestSent”) }).defer();
* Ajax.Response: Now you can more easily work with JSON
* DOM Builder
* Template API: “#{last}, #{first}”.interpolate({ first: “Andrew”, last: “Dupont” })
* Improved support for JavaScript 1.6 and WHATWG 1.0 standards

Be sure to take a detailed look at this puppy.