One of the minor issues I run across with surprising frequency is the question of what color is that on my screen? I need to know the digital value of a color when working on photo books and on my web site. I just ran across a marvelous little tool built into OS X: Digital Color Meter. It doesn't do much, just gives the color value of what is under the mouse pointer at any given time. A quick easy solution to my need.
More on this tool at other sites. Tech Republic has a whole page on this handy little critter.