This hint was inspired by a study that found red wallpaper conducive to detail-oriented work, while blue wallpaper works better for creative work. Based on that, I wrote a simple AppleScript to display a dialog that allows the user to choose between working environments. The script then sets the desktop picture based on the user's selection.
Note that this hint assumes you've already created the new solid colors (very dark gray, very dark blue, and very dark red) as explained in this previous hint. Once you have those colors (or others, if you prefer; just change the script as necessary), create the following AppleScript:
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090505222800665