I just created our first Firefox Persona and it is available for you here:
Not sure what a "Persona" is? Firefox allows you to customize your browser to your taste. A Persona is the background graphic behind all your tabs, menus, and bookmark links on your FireFox Browser. If you go to the link above, you can, without committing to anything, "hover" over any of the Personas and see what changes are taking place. If you don't like them, just don't click on them.
Not sure how to "wear" the persona? No problem, it's actually pretty easy. Go to the link above, hover over the image to see the changes take place, then click on the "wear it" portion of the image.