This is pretty easy. In all 3 of the areas you trick or treat in there are 3 Apple Bobbing mini-games. When you win talk to the same person again to start the second/third level.
Simple concept: Grab apples that are whole and avoid the cores/with worms. You get 1 point for the red apples and 3 points for the green ones. I'd recommend going for the green apples as much as possible, but make sure you don't abandon any red apples because your waiting for the next green.
The requirements for the different games are as follows:
Park in Auburn Pines: 20 - 25 - 30 Points
First floor of The Mall: 25 - 30 - 35 Points
By the Ferris Wheel in the carnival. 30 - 35 - 40 Points