(disclaimer: I have approximately as much knowledge of horror movies as I have knowledge about pop music - which is to say, almost none at all.)

Beat 1: Teenagers are upset at all the rules parents put them through.
Beat 2: They decide to have a crazy bash in the woods.
Beat 3: On the way there, they start losing cell reception.
Beat 4: The teen whose place this is says there's nothing to worry about; they have a land line.
Beat 5: The teens don't worry and party hard on their first night.
Beat 6: During the first night, when someone trips and disconnects the power for a short time, someone sees "something" in the woods, that creeps them out.
Beat 7: The next day, that teen decides to expresses concern for being so far away.
Beat 8: No one else is concerned.
Beat 9: When the power goes out again, with no one outside, they decide to go see what happened.
Beat 10: They find that the same spot that was tripped over and repaired before, is now frayed and looks like it was "pulled apart".

Think I just used up my creative juices for a couple of hours. Anyone else feel like continuing this with additional beats? Try to keep it going that there's an invisible "therefore..." or "but..." before each beat. Keep a few "they decide" in there so the characters remain actionable.