Boxing Day is a (Mic) minigame in Mario Party 7. In this minigame, one player uses the Microphone to control the arms of a big robot while the other three players try to reveal the hidden picture beneath the tiles they're walking on by using the Ground Pound. In order for the player in control of the robot to win, he or she must give it commands by speaking into the Mic in attempt to knock all three of the players off the stage before they succeed in ground pounding all the tiles on the stage. If the three other players do succeed in ground pounding all the tiles on the stage, then they will win the minigame.
For player in control of the robot: Say "Left" for a left punch. Say "Right" for a right punch. Say "Double Punch" for a double punch. Say "Rotate" to rotate the robot with its arms stretched out. Say "Rocket Punch" for a rocket punch.
For the other three players: Use the control stick (or right thumb stick) on the Nintendo GameCube controller to move, the A button to jump, and to Ground Pound, press the A button twice.