Make a Facebook background for my profile or page

Is it possible to modify your Facebook background?

One of the strengths of Facebook is the fact they insist on keeping their general profile layout as clean and uniform as they can. That said, they still allow their users to make some degree of graphical customization in their profiles via applications like Facebook expressions, which allow you to create custom backgrounds or wallpapers that you can use for decorating sections of your Facebook profile but not the entire page (as it is possible on MySpace).