Taking full advantage of the upcoming features in the PHP 5.3.x series (and in PHP6 for that matter), Joshua Thompson has come up with a way to accomplish some prototype-based programming in a PHP application:

With the implementation of the get_called_class() function in PHP, prototype based programming in PHP is possible. The new function is in both PHP5.3 and PHP6 snapshots. So, I went back to the drawing board and came up with a fully capable class. The $this keyword is usable, as well as being able to use the self, parent, and static (new with the late static binding patch) keywords.

Prototype-based programming is (basically) a method where classes aren't prebuilt. Instead they are created on the fly based on other objects and interfaces. Joshua's post is a huge code dump of a prototype class and an example of it in use, dynamically creating two methods and making the three objects available.