PadRacer is a racing game that uses the iPad and the iPhone (up to 4) to play
The iPad is used as the gameboard and each car is controlled by an iPhone (or iPodTouch with WiFi or Bluetooth), holding it upright like a steering wheel. The iPhone controller (Pad Racer) app is free
& downloaded here. Download the iPad part here.
This video explains this better:
The game was made by Hong Kong company, SMHK.
What a smart way to integrate the iPad + iPhone, I can’t wait until more companies use this. This really shows how the iPad could be competition for game consoles.