Drop the block definition (the big purple part, not the block) into your projects for full RGB color control. "The RGB color model is an additive color model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors." https://en.wikipedia.org/wiki/RGB_color_model You can play with it here by playing with the sliders. Have fun! Please love and/or favorite if you do. And if this is helpful to you, credit would be nice.
I discovered that Scratch 2.0 allows for variables to be placed on the color on the "set pen color to" block.. and after more toying around, that it takes a integer representation of RGB: ([red 0-255] * 65536) + ([green 0-255] * 256) + ([blue 0 - 255]) (Discovered while working on my WMD2 Project. Also see that for work on HSV conversion for better color picking.) Credit goes to DarthPickley for suggesting that I make it into a block and simple project, and use floats as inputs. A 0 to 255 version is also included for exact control of each of the 16,777,216 possible colors.