Nintendo Wii Numchuk Controller

The Nunchuk controller is designed to work together with the Wii Remote on
the Wii video game system.

Contoured to fit perfectly in your hand, the Nunchuk adds extra buttons, an
analog joystick, and additional motion-sensing control to expand the game play
possibilities.

Here is a list of games that require the nunchuk to play.

The Legend of Zelda "The twilight Princess"

Wii Sports "Boxing"

Madden 2007.

Red Steel

Call of Duty 3

Wario Ware: Smooth Moves

Rayman Raving Rabbids

And many more