As you've probably read, we've created a generic scripting environment for Orchard, currently supporting PHP scripting (C# and VB coming soon) usable as an action with the Orchard Rules engine or in views with the PHP view engine. PHP scripting employs Phalanger to run PHP inside .NET. Since Phalanger currently lacks support for .NET dynamic objects it was not possible till now to modify Clay objects, that in Orchard are used mainly for shapes. This meant that e.g. you couldn't write proper shape overrides in PHP for display shapes that generally have a dynamic Model injected.
Ironically using dynamic shapes in the dynamic PHP language can be made working with statically typed objects. With the new PhpShape class that proxies calls to an underlying shape PHP scripts now can embrace the full power of shapes! See the PHP scripting documentation for examples.