Toys are designed to be fun and playful and are highly motivating for both children and adults. Commercial toys and child-designed toys can be used both in the classroom and at home to encourage creativity and to teach science concepts. Much of what children can do with toys involves tinkering, defined by Merriam Webster as "to repair, adjust, or work with something in an unskilled or experimental manner: fiddle." Children (and adults) can tinker as they take toys apart, experiment with them, and design toys for themselves. This paper is inspired by workshops the authors conducted at the International Toy Research Association (ITRA) conference in Bursa, Turkey, 2011, and the IPA World conference in Istanbul, Turkey, 2014 as well as activities we used in our classes.