Not laughing at all.
Value is the amount of light in a particular fabric - relative to the fabrics around it.
Rather than me go on incoherently about the value of value ;-),- here are some other explanations.
(FYI - You don't need the tools - most of the time it's very easy to discern value. However, the easiest way is to just copying/scanning the fabrics and printing/viewing them in b&w. It takes the color out and you'll get a greyscale image showing only the value.)
http://www.karencombs.com/freevaluelesson.htm
http://quiltbug.com/articles/color.htm
Successful quilts are ALL about value. You might not realize it, but it's the first thing you see (or don't), when looking at a quilt. Because without it, you really can't see the pattern.