ooooh, I love it! I love purple! I'm getting ready to overdye a bright green cashmere blend I recycled, and I think I might go for purple.
mathwizard, koolaid dyeing is so easy! It doesn't fade, but it can only be absorbed by animal fibres, or animal/nylon blends. So no synthetics (acrylic, etc) and no natural fibres (cotton, etc). The only exception I've seen is the Soy Wool Solids/Stripes which is a wool/soy/nylon blend and I know from experience it dyes excellently.
The great thing about koolaid (or other drink mixes... crystal light, store brand stuff) is it already has citric acid in the ingredients, so you don't need to add vinegar or anything when you use it. Just make sure you're not using the sugar-already-added koolaid. Otherwise, it just works the same, in the microwave, crockpot, pot on the stove... heating until the dye is absorbed, rinsing, drying.
oh, and it makes your house smell really good while you're dyeing it!