I started growing celery from the bottom of a store-bought bunch. I never knew you could do this, but it's doing great. I transplanted it in one of the boxes after letting it sit in a bowl of water for a few days.
I also am planting a pineapple from the top of a store-bought pineapple.
I pulled the leaves off the bottom, let it air dry for a few days then placed it in a mason jar filled with water. It took about 3 weeks until new roots started growing.
In about 14 months, I should have a new pineapple ready to harvest!