From the Multiplayer menu, choose to play Frenzyfest (minimum of 2 controllers required) then put your second controller on one side since you don't need to touch it. Play one 9-round game and one 3-round game as you only need to win 5/9 rounds to finish but you will still get all 900 points. You will get the remaining points from the 3-round game. The rounds are made up of randomly selected mini-games ranging from "tail biting", "starfish collecting", "tag" and more. None of which are too long or difficult. Read the rules before the start to make sure you're doing the correct task. Some of the games are timed, some will end when you reach a certain score.
The trophy will pop on the "awards" page after the final round has been completed.