Kool Aid will do nothing to the color of your plant, I think people get this idea because they've seen cut flowers like carnations colored through the uptake of colored water. Like someone said about the Sugar, Molasses will feed the beneficial microbes in the soil and it come down to happy soil, happy plant. I always add molasses to all of my plants in soil media with every watering to try and keep the soil as active as possible(1table spoon of molasses to 1 gallon of water). As for just adding regular sugar I believe all this will do is bring pests. As for good color, the things that usually affect color in plants is light and temp (nutrient def. can also cause odd coloring). As for Marijuana I know that as the temps get colder that's when you will start to see the color in your plants. Think of Fall as plants start to go into dormancy the leaves change red, yellow, purple, orange, and drop.
as to WHY the plants are different colors that is a different story.
Once you know your core growing techniques is when it is best to start breaking the rules. That's something I always like to remind people as they are starting out with their growing.
and remember a dirty hoe is a happy hoe!