Some of my young nieces/nephews are able to play a penguin game. It is called Racing Penguin and I'm pretty sure it was free, at least for the demo. Pretty simple game since the only control is a touch (which makes the penguin tilt down to accelerate) or not a touch (which lets the penguin fly). Timing gets important for the harder levels, but the basics are easy enough for anyone without requiring any fine motor skills. And it's kinda fun to see the penguin go flying through the air.