Toddlers love to color and will usually color on anything and everything if you let them. Try this idea if you have a runaway artist in your home.
Large sheet of drawing paper
Tape a large sheet of drawing paper to the easel.
Cut several pieces of yarn about 2 feet in length.
Cut a small notch at one end of each crayon and wrap and tie a length of yarn around it.
Tie the other end of the yarn to the top of the easel. (Be sure to cut the yarn long enough to reach the paper, but not so long that it poses a choking hazard.)
Now your toddler can scribble any time she wants without waiting for you to set out the crayons and paper.
If you don't have an art easel but do have an empty wall in the basement or playroom, use that instead. Tape a large sheet of paper to the wall. Above the paper, hammer in a few nails and attach the yarn and crayons to the nails.