The person with the most correct answers wins. Set up teams, giving each team a bag, a folded list of around 10 items to search for, and one flashlight. Then clearly state the boundaries of where they can search and send them off, making sure to remind them to keep with their group and stay close to the person with the flashlight so they don't bump into things. Finding things in the dark isn't the simplest of tasks, so keep the list easy and have them search for items such as a clover leaf, a berry, a pine needle, some moss, etc. The first team to find all of their items is the winner.
Flashlight tag is also a great after dark party game for the backyard.
Once the children are hidden they must turn off their flashlights and remain silent. Replace one of the lights in your party room with a black light bulb and turn off the rest of the lights, then have your guests grab their overnight bags and search for any item they brought that glows. Only the items within the contents of their bag count and whoever has the most items that glow is the winner. Fill an overnight bag with several small identifiable items such as a bottle of nail polish, a toy car, a Q-tip, a marble, etc., and let each guest feel around in the bag without looking. Then after everyone has had their turn, have each of your guests write down all of the items they can remember.