10 Have over 20 minutes of "Berserk Time".
Find the Berserk power up on a map in multiplayer and wait for it to respawn and then rinse and repeat. It takes super powerups around 90 seconds to respawn. You could get this more easily with another controller as you don't have to be worried about getting attacked. Setting to game to 1 hour will help.
All I did was set the contestants to 1 (Me) and just sat on the item spawn. Walked away, watched SpongeBob, came back and had the achievement.