From PhysX Wiki
Switchball is a 3D action-puzzle game, made by Swedish developer Atomic Elbow, which was released for PC in late June of 2007, and on other consoles (PS3, Xbox 360) in the years following.
The game consists of solving puzzles by guiding a marble through a suspended course in many different environments. Switchball uses Ageia PhysX engine to simulate the reaction the marble makes with its environment. The game is called "Switchball" because the marble can be morphed into different balls with unique physical properties.
Example, a Steel Ball (which can push heavy objects around) or a Power Ball (which can be charged for magnetism, power boost, jumping, etc). Each course contains physics-based obstacles and traps which the player must navigate around.
Switchball was not only one of the first PhysX SDK based games (technical demo of Switchball was bundled with first Ageia PhysX cards), but also featured a full scale support for Ageia PPUs - several levels in the game (marked with "PhysX by Ageia" logo) have included special puzzles, mostly showcasing SPH-Fluid simulation, available for users only if Ageia PPU was found in the system.