Two dishes, some water, and a medicine dropper from the pharmacy. I filled one dish, and left the other empty, and encouraged Zeke to move all the water from one dish to the other. Which he did, numerous times. I left the water plain, nervous about how well Z would be able to control the dropper, but he did great, it was the perfect amount of difficulty for him.
I think with some food dye and a 3rd bowl this could be a really fun color-mixing experiment. Or even a fun art project, dripping food dye or watercolors onto paper. So there you go, 2 household objects and 3 possibilities.