Extendable by design
The MODx community has created many add-ons which can be found in the Repository, from image galleries and e-commerce to smaller utilities.
Template Variables with Bindings
TVs - Template Variables - are powerful extra fields that you can use with your documents. As an example of an advanced template
element that returns a different thing dependent on code or data, we created an @BINDING for the name of the Login menu item.
This changes the menu name from Login to Logout based on your logged in state. The @BINDING as follows was placed in the default value as:
@EVAL if ($modx->user->hasSessionContext($modx->context->get('key')) return 'Logout'; else return 'Login';
Using Mootools
We used some simple effects to highlight various things on the front/home page to demonstrate how easy it is to create a useful way to draw attention to things.
Custom Forms
To demonstrate how to link to custom forms, we customized the calls to the Registration system and the Login system.