A small tool for finding colors. You know the eyedropper tool in Photoshop that can pick up a color from an image? This will do something similar for anything visible on your screen. It will grab the RGB value of the color just underneath your cursor, in any Windows program.
Download it here (zip, no installation needed). Run the program and press the space bar to update the color to be whatever color is beneath the mouse. The idea came from altAnswerColor from Altuit.
Update: finding the current color with this tool apparently does not work in Windows 8 or other recent operating systems.