FlyFlyFly is a very simple game to test your reaction and timing sense.

You will be presented with a single screen with paper in the background and a fly in front of you flying randomly all over the phone.

Your goal in this game is to kill as many flies as you can, one by one, without missing a single time. Compete with players around the world and prove you're the best fly hunter!

To catch the fly with a swatter, just touch anywhere. Do so ONLY when it is inside the pencil-drawn circle in the center of the screen.

So basically, you have to exercise patience and wait till the fly gets into the circle (usually it takes at least a few seconds, but sometimes it won't fly around the center for a longer time) and SMACK it down!

Source: http://itunes.apple.com/th/app/flyflyfly/id441926995?mt=8