We will be posting CSS hacks to radically customize your site including things like changing the dimensions of areas on your site, changing background images or colors, and a whole lot more!  Hacks will be categorized by template name and more will be added by request.  Eventually these hacks will be implemented using a menu system.  For now they can be included either from the "CSS customization" link on the left side of the interface, or in the "CSS rules" area when editing a page (may be disabled by default, ask for help enabling it if you prefer to do css on a page by page basis instead of universally).