Your documents - listed how you want them
MODx Revolution's document data structure has been designed to allow many different routines to redisplay the information in ways that suit your needs, such as a dynamic menu in your template.
Two of the most widely used menu constructors are Ditto and Wayfinder.
Wayfinder - the menu builder
Allows you to template every part of the menu. On this site, Wayfinder is being used to generate the top bar menu and the links menu in the sidebar but many types of menus and sitemaps are possible.
Ditto - the document lister
Uses include listing the most recent blog posts, producing a site map, listing related documents (using a TV filter) and generating an RSS feed. You could even write a menu with it. On this site, Ditto is being used for the Most Recent documents generation and the RSS feed example.
If you can''t quite get your desired effect using templating and the many options of Ditto and Wayfinder, you can write your own routine, or look for other packages using the package manager sourced from the MODx Revolution repository. MODx Revolution's fields for Menu Title, summaries, menu position etc can be used via the API to produce anything you can imagine.