Pottery Wheel is an app that simulates shaping a piece of spinning clay. The player can carve with a finger using the Leap Motion Controller.
Pottery Wheel was created with Vuo (http://vuo.org), an environment for creating prototypes, apps, and videos without having to write any code. Vuo gives developers and non-developers alike a simple interface for creating sophisticated 3D effects based on OpenGL and GLSL.
In Pottery Wheel, if the player doesn't have a Leap Motion Controller plugged in, the app falls back to mouse controls. Vuo makes it easy to tinker with different kinds of user interaction, including the Leap Motion Controller, mouse and keyboard, OSC, MIDI, and serial devices like Arduino.
You can download Pottery Wheel as a Mac app, along with visual source code to open and play with in Vuo.