Choose a couple of friends to serve as actors and help you enact a scary skit. Gather your friends around the fire and make sure you can see everyone above the flames. Hold a flashlight under your face for effect. Have your actors act out the story you tell. One might be a girl wandering through the forest at night, and the other might be the killer. As you tell the story, the killer might hide in the circle with the rest of your friends, then jump out to chase the girl around the circle.
Do some research into the area where you have your fireside skits. If you're in the Appalachian Mountains, perhaps tell tales of the Civil War, or if you're in the Midwest, tell tales about Indians and settlers. Have some actors help you enact these historical tales, or create the entire skit on your own, playing all of the roles. Skits about the history of your area will both inform and entertain your friends.
Research stories about bears -- either bear attacks or tales of great escapes from them. Have a friend hide in the woods away from your other friends while you enact this story. Perhaps you're telling the story of a hiker going into the woods by himself. Enact the trips and falls, the difficulties of making it deep into the woods. Just when you come to the point of seeing a bear, have your friend jump out from the woods and scare the others.
Rally your friends to join in an improvisational skit around the campfire. Begin a scene with only two people acting together, and allow them to set the scene wherever they like. Then people around the circle will call "freeze" and replace one of the actors, continuing the same scene. Make sure people don't jump in too quickly. You want the scenes to develop before anyone else jumps in. Continue the scene until everyone has had a turn and the original actors are back on their feet. It's their job to bring the scene to an end.
Another improvisational skit that's really fun around a campfire is to have your friends parody one another. Have a few friends re-enact your journey to the campsite, and guess who they are. Allow the scenes to develop before making guesses. To spice things up, create similar skits, but have each person impersonate someone famous.
