The Zombie Island Of Dr. Ned: Unlimited experience
After activating the three turrets in Jacobs Cove, one of them will be down and not be scanning the area for zombies. Attack this turret to make the shield go down and damage it. If you damage it enough, the turret will explode but not disappear, giving you 1,296 experience points, a random level 48 shield item, and some experience for whatever weapon you where using to attack the turret (on your second playthrough). It has a very large amount of health. Note: Using a weapon with acid damage is best for the increasing bonus damage. This can be repeated an desired your second playthrough.