Up on nearfuturelaboratory a very interesting project is being developed. PSX is a design for controller of PS2. It uses a Flavonoid device and requires the user to generate fuel for the controller as he plays along. The player starts with an initial supply and must then proceed to generate his own to prevent the controller from stopping altogether. So in effect the controller is being used to generate artificial fatigue in the game. The designer uses GTA and Katamari Damacy to illustrate the working of his PSX. So as the guy (in GTA) does running and robbing, he actually gets tired and sluggish, until he completely gives way. Similarly in Katamari, as the Prince rolls along, he gets weary. The designer describes:

The “theory” embodied in the PSX controller is meant to disrupt the conventional understanding of the relationship between physical activity in 1st Life and virtual-physical-digital activity in 2nd Life digital worlds.
The project is taking two approaches – a digital (involving modifying the communication between console and controller), and an analog one (involving insertion of an Arduino in the controller). The technical mumbo-jumbo can be read right here.