OS X's Desktop & Screen Saver panel includes a "Solid Color" selection, where you can choose from one of 10 different solid colors. But what if you want an all-white background? It turns out there are actually 11 solid colors on that panel; the 11th is all white, and is positioned just after the last light-blue panel. It's highlighted in the image at left (larger version) with a dotted outline, but you won't see that nice visual aid when you use the actual panel. And it won't work if you click on just any white space in the color area; you need to click directly in the box-sized area outlined.
[robg adds: I'm not sure why Apple hasn't highlighted the white box, as most people (myself included!) probably won't even realize it's there. An older hint explains a different techique (check the comments for further enhancements) for getting any solid color you wish as a desktop background...]

