Map->Image is a webapp that turns maps into awesome large images in a variety of styles. You can use it to create a new, unique wallpaper for your desktop.
Created by Stamen Design, the open-source utility asks for a location and then shows you a bunch of options. These include watercolor, high-contrast black and white, heat and terrain maps. (Terrain maps are available in the US only, but the others mentioned here are available worldwide.)
You can specify the size of the image output (up to 2000 x 2000 pixels) and then get a link to the downloadable JPEG.
Isn't that neat?