This is a nice little project to do with kids. You can grow sweet potato vines in spring or even during winter. Sweet potatoes are really simple to grow. In spring, you can just plant them in your garden or pots and water them regularly.
In winter, you can dip them in water and keep them in warm places. In that way, you will have beautiful sweet potato vines when spring comes. By the way, do you know that sweet potato leaves are edible?