The WII Fit is an accessory in the form of a bord to step on, whose main purpose is to allow the WII to sense the player's feet movements, thus allowing for fitness coaching games, dancing games, and any activity based on leg movements.

Here's an example video :

NINTENDO Wii FIT PLUS WITH BALANCE BOARD NEW


NINTENDO Wii FIT PLUS WITH BALANCE BOARD NEW

Price: $123.50
NINTENDO Wii FIT PLUS WITH BALANCE BOARD New 2010


NINTENDO Wii FIT PLUS WITH BALANCE BOARD New 2010

Price: $123.01
Silicone Balance Cover Skin for Nintendo Wii Fit Board


Silicone Balance Cover Skin for Nintendo Wii Fit Board

Buy It Now: $8.89
FOR WII FIT GAME BALANCE BOARD & 4 REMOTE SKIN CASE NEW


FOR WII FIT GAME BALANCE BOARD & 4 REMOTE SKIN CASE NEW

Price: $14.49
Buy It Now: $15.95
NINTENDO Wii FIT PLUS GAME ONLY BRAND NEW


NINTENDO Wii FIT PLUS GAME ONLY BRAND NEW

Price: $14.50
2X New Wii Steering Wheel Controller fit Wii Remote


2X New Wii Steering Wheel Controller fit Wii Remote

Price: $0.99
Brand New Wii Fit Plus with Balance Board


Brand New Wii Fit Plus with Balance Board

Price: $88.11
FOR WII FIT GAME BALANCE BOARD & 4 REMOTE SKIN CASE NEW


FOR WII FIT GAME BALANCE BOARD & 4 REMOTE SKIN CASE NEW

Price: $14.49
Buy It Now: $15.95
Rechargeable Battery Charger for Wii Fit Balance Board


Rechargeable Battery Charger for Wii Fit Balance Board

Price: $7.51
Buy It Now: $8.28
NEW NINTENDO Wii CONSOLE Wii FIT PLUS MARIO KART BUNDLE


NEW NINTENDO Wii CONSOLE Wii FIT PLUS MARIO KART BUNDLE

Price: $400.00
One-Tone Smooth Anti-Slip Sleeve for Wii Fit Board


One-Tone Smooth Anti-Slip Sleeve for Wii Fit Board

Buy It Now: $8.89
NEW 1 NINTENDO WII GAME CONSOLE + WII FIT PLUS BUNDLE


NEW 1 NINTENDO WII GAME CONSOLE + WII FIT PLUS BUNDLE

Price: $317.00
New Nunchuck Controller Fits Nintendo Wii


New Nunchuck Controller Fits Nintendo Wii

Price: $0.01
MGEAR Green 4 in 1 Bundle For Nintendo Wii Fit


MGEAR Green 4 in 1 Bundle For Nintendo Wii Fit

Buy It Now: $49.29
NINTENDO WII CONSOLE SYSTEM+ 4 CONTROLS+ WII FIT BUNDLE


NINTENDO WII CONSOLE SYSTEM+ 4 CONTROLS+ WII FIT BUNDLE

Buy It Now: $807.44
2X New Wii Steering Wheel Controller fit Wii Remote


2X New Wii Steering Wheel Controller fit Wii Remote

Price: $0.01
SKIN CASE COVER FR NINTENDO WII FIT BALANCE BOARD BLACK


SKIN CASE COVER FR NINTENDO WII FIT BALANCE BOARD BLACK

Price: $9.15
Buy It Now: $10.07
NEW NINTENDO WII CONSOLE+ WII FIT PLUS 2 PLAYER + GAMES


NEW NINTENDO WII CONSOLE+ WII FIT PLUS 2 PLAYER + GAMES

Buy It Now: $479.88
New Nunchuck Controller Fits Nintendo Wii


New Nunchuck Controller Fits Nintendo Wii

Price: $0.99
Wii Fit Plus With Balance Board


Wii Fit Plus With Balance Board

Price: $86.01