Mitcho created a great WordPress plugin and a video tutorial on WordPress.tv.

The great features of HookPress were well explained clearly by Mitcho, the HookPress author.

With HookPress on WordPress, you can

• create Post webhooks
• create push notification (it supports both actions...)
• create filters

The bottom line is that you can extend WordPress without PHP

Here's the video:

Mitcho is a MIT Linguistics PhD student. He has another "must-have" WordPress called "Yet Another Related Posts Plugin", also popular among WordPress users. Way to go, Mitcho!

To install HookPress, just go to "Add New" Plugins menu in your backend (Dashboard), and search for "HookPress", then you can have it automatically downloaded and installed with a couple of clicks. If your hosting server does not allow you to do that, you may go to http://wordpress.org/extend/plugins/hookpress/ to download and install it.