To dye your own yarn:
First, you'll have to haul your sorry hungover ass out of bed to buy a microwave-safe container and a crappy pot. There's really no way to avoid this unpleasantness.
If possible, try to avoid spilling coffee all over yourself three times while walking to the housewares store. If you attended your corporate holiday party the night before, the yarn gods will understand if you do not succeed in this.
Second, assemble your components while you give your yarn a nice bath in some lukewarm water with a bit of mild detergent. Some people use a special yarn-friendly detergent like Wool Wash. I just used my regular Method stuff.
Take a moment to marvel at how the yarn really does look exactly like spaghetti. Give it a few gentle squeezes while you're there.
Mix more Koolaid than you think you need with a bit of water in a microwave-safe container. The rule of thumb is one packet per ounce of yarn.
Do not blithely assume that your yarn label will tell you how many ounces of yarn you have in your skein. It's possible that your yarn will be measured in grams. If you don't have your laptop with you or any grasp of basic conversions, just use all the damn Koolaid you have. I used a 4-cup Pyrex measuring cup, and a total of 20 Koolaid packets for two 440 yard skeins. Next time, you will probably want to use more Koolaid.
Place yarn in microwave-safe container with the Koolaid.
Freak out a little bit that you are about to put yarn IN THE MICROWAVE, but assume all the nice bloggers were not playing a cruel practical joke when they suggested doing so.
Microwave on high at two-minute intervals, waiting a few minutes in between, until water is mostly clear. Mine took six minutes for most of the dye to be absorbed.
You can also set the dye on the stovetop, but the microwave method seemed easier.
Allow yarn to cool, then rinse in lukewarm water.
If you want to hand-paint for a more mottled effect, put your yarn in something that you don't mind getting messy. Pour dye all over as desired. I'm pretty sure there's no wrong way to do this. I dribbled some fruit punch on, then dipped the whole thing in a mix of orange, cherry, more fruit punch and lemonade. Then just microwave as above.
Finally, do wear gloves. You may think you can just touch the dye quickly, then rinse your hands immediately. But you will be completely wrong.
After a thorough rinse, spread your yarn out to dry.
And be sure to stroke it lovingly every time you walk by.
I seriously can't remember the last time I had this much fun with my clothes still on.