If you have a sliding glass door or a big window within your child's reach, hand them a few dry erase markers and see what they come up with.
Let them draw what they want....
....or, turn their dry-erase session into an educational experience.
Have your child complete a pattern, or practice writing their letters and numbers. Have them draw a picture from a story you read earlier....or tell them to draw a picture of something that rhymes with ______.
Lots of fun. And it keeps them happily occupied for a nice long time :)