RGB2NAME returns a string containing the name of the input RGB triple. (Or a cell array of strings if an array is input.) This is a "brute force" approach that contains a large list of colors and their names, and uses a very simple nearest neighbor search to find the named color that is closest to the input color.
The included list has more than 400 color names, and it performs pretty well. There are a few regions of the color space where it isn't great, particularly with low-saturation colors.
This is mostly just for kicks, but I made it for a GUI that needs to ask the user about unnamed hg objects, so instead i can describe them to the user by color. Like "...the graph with the light red and very dark green lines..."
There is also a demo included (requires java) that names colors selected by the user in a jcolorchooser.