Overview

The wiki is flexible and formatting + content can happen in several ways;

Wiki Markup Language - accepts wiki-specific markup + some HTML elements, see Wikipedia - [1]
Wiki Templates - using the {{}} markup - you can invoke templates defined as {{Template:______}}
CSS - CSS is handled within Mediawiki, example is CAD_Current_Work#GVCS_Projects_-_CAD_Status
HTML - using HTML, you can embed content from other platforms, such as Google Docs, WebGL, and much more.
HTML/CSS/Javascript - see Flashy XM for a combination of Wiki Markup Language, HTML, CSS, and Javascript

Wiki-Specific Templates