If you are ever looking for an activity to keep a small child entertained, give them water and a paint brush and ask them to paint the deck or driveway.
You will be quite surprised how exciting this is for todlers.
Often, parents do not like young children to use paint because it gets messy, but this is the perfect alternative. Check out Niels Shoe Meulman's work called Calligraffiti. He still uses water!