Tonight for dinner, grapes were the bargaining chips (in exchange for spaghetti squash, mostly). Ethan decided he wanted two grapes. I told him that to get two, he needed to earn one (a bite of squash), not eat it, and then earn another. It took a few tries, since the grapes are so tempting, but he figured it out. After enjoying the fruits of his labor, he decided he wanted three grapes. He saved up for that, too.