Start with a line of players.  The first two will come up to the buttons.  Each player two colored buttons in front of them.  The person on the right has red & blue while the person on the left has yellow & green.  Once the game starts the two robots will start punching each other.  At a random point, a color will appear over each robot.  Be the first to hit the button corresponding to the collor.  Best of three wins.  The winner will return to the end of the line, the loser will sit down.