Hopscotch is a great programming environment available for iPads. It is a lot like Scratch, but designed for the touch screen interface.
Here is a YouTube video that provides step by step instructions to make a "Tapper Game" - a game where you are trying to tap an object as much as possible to get points. These instructions give the basic ideas and concepts, you will need to provide the game ideas!
Tapper Game in Hopscotch YouTube Video