Go Away, Boo!
From the Super Mario Wiki
In the upper right hand corner of the main London Map, players try to stay away from either Boo or a person with a Boo. Players with a Boo need to tag a person without a Boo to pass it off. But if the player does not do this within ten seconds after a three second signing time, the player is eliminated and remains in place and the Boo leaves. Their are two Boos at the start of the game, but goes to one Boo if two players are eliminated. The game ends when either the 45 second timer runs out or only one player remains.
Wii Remote held sideways
Wii Remote and Nunchuk
Objective: Stay away from Boo and stay in to win!