Bright Nights

Bright Nights is a week long event that starts on the second week of February in Animal Crossing: Wild World. During this week, all of the villagers will decorate their houses with lights. You'll be able to judge which one is the best of them all, and then subsequently telling the mayor whom you've chosen as the winner. After this you should tell the villager that he or she won, as doing so will cause them to give you a special gift.