Corn husks - if you grow or buy corn, save the husks to make corn husk dolls and flowers. There are some really beautiful things you can do with cornhusks. Again, check out nature craft and old-fashioned craft books at the library. After you harvest your cabbage, pot up the root, leaving the top visible and bring it inside. You can do this with many garden plants.
Herbs make beautiful houseplants too.
Just clip a few tender sprigs, and put in water. After about 5 days, roots will start to form. Keep the sprigs watered, changing water if it gets murky. Dip them in lemon juice to reduce browning. You can dry them in rings, stringing them up to dry, or as slices.