A while ago I made a game called: Circle the aardvark in the back of the pickup truck. Now, by popular demand (or just because I felt like it...), I've posted the code and resources for public download. I think there's a lot of potential for using the core mechanic (circling things) for other games for touch devices. I intend to do a series of posts explaining some of the important or innovative aspects of the code.
In the meantime, the code can be found here.
Topics I hope to cover are:
Discrete random distributions
How to know when a circle (n-gon) is closed
How to know which objects are inside a closed circle.
Global timer control
High scores tracking with php and an sqlite database