The work table, the undyed yarn (knitpicks), the dye (Hello Yarn), the vinegar, the plastic wrap and bags, the gloves, the microwave. Simple ingredients for FUN! I'm not great at this yet, but that doesn't take away from the fun part.
It's pretty hard to get something you really don't like, and you can always try going over it again anyway. I've done koolaid dyeing, too. Fun AND smelly.