A tap controller for Unity3D for mobile devices (iOS and Android).
Just drop the file into your project and attach it to a game object.
There is a guide here: http://honkbarkstudios.com/developer-blog/tapcontroller-unity3d-tutorial/
Take a look at the TapController example in the UnityExamples repo
This tapcontroller is used in production in the game Friendsheep