Here are my koolaid dyed yarns:
I used a snow-white Brown Sheep Company (it costs more, but I'm Nebraskan, I gotta support our own!). I don't need to felt, and I wanted the colors to be true. I can't recall exactly which colors I used at this point, it's been awhile. But I do remember that the grape had to be overdyed several times to acheive a mediocre purple. Also, Koolaid makes a flavor like iced apple, or some such thing, that produced the most gorgeous pale pistachio color. I was very pleased with that. The iced lemon flavor made a sweet butter yellow. Those are on the right side of the bottome picture (the colors don't come through in the photo as well as they might, but that's okay).
I bought a sweater at the goodwill, which was two wools and a silk yarn in brown, camel and cream, entertwined. I unravelled it and dyed it in blue, to make a beautiful brown-and-teal yarn. No pictures (it's packed at the moment) but it worked really well.