Beautify lets you add a personal touch to your boards on Trello.com (Trello is "a collaboration tool that organizes your projects into boards.")
As of release (v1.4), the extension lets you choose new colors for the Trello header and board. Also, you can "upload" a background image from your computer to really make your boards stand out. Finally, there are a few usability toggles to make reading Trello easier.
As an added bonus, this extension is presented in an unobtrusive way that matches Trello's existing menu style!
** release v1.3 Introduces card coloring, based on the labels you attach to a card **
** release v1.4 addresses a few bugs & introduces usability options, like 'shadow mode' **
Browse the screenshots to get a feel for the types changes you can make with this extention. By all means, leave comments & ratings here on the extension page - it's worth noting, however, that bug support and extended community feedback will be handled on the public trello board.
Also, please know that this extension was not developed by or in cooperation with the good people at FogCreek (the makers of Trello). This is a hobby project.