Twenty one "problems" wait to be fixed, in four zany cars designed with typical boy and girl (pink and ribbon) themes. After you choose a car, you see the problems for each, highlighted. There's a lot of sorting, connecting wires of the same color, connecting circuits, patching leaks, tracing a path to fix a fan belt, and so on. Each time you solve a problem, you earn a badge which is saved from day to day. Innovative features include tilting the screen to pour the oil, and turning your screen upside down to look under a car on the lift. We also liked some of the underlying concepts in some of the games, like connecting paths to complete circuits, the introduction to oil and pistons, the parts of a wheel, replacing windshield glass and so on. There are different difficulty levels and no high scores. When all the activities are complete, you start over. This is a fast, fun, irreverent app with some hidden surprises that encourage frequent visits; in other words, you'll get a lot of mileage out of this well designed app.