Over the weekend I purchased a very nice iPhone game called Flight Control. The game is easy to use, takes advantage of the iPhone interface, is cheap ($.99), and most importantly is fun to play.
In the game you are flight controller responsible for getting various types of aircraft to their respective proper landing areas without running in to each other. The controls are simple and effective. To guide a plane to the proper runway you touch the plane and then draw out the path with your finger.
The games are fairly quick, so it is ideal for those situations where you just want to kill a few minutes, or to entertain the children for a few minutes.
I am fairly picky about purchasing applications for the iPhone, the mobile app store makes it easy for you to go a little over board if you aren't careful. And, I don't usually purchase games; the iPhone is expensive and I try to do plenty of "grown-up things" on it in order to help justify the cost. But, this is little game is definitely worth the $.99, it is the best game that I have.