You could get a sheet and cut holes in it for your eyes and nose, and be a ghost.
Get a black pointy hat and a black dress and go as a witch.
Wear some old clothes such as bell bottoms and do your hair like they did back in the olden days, and go as a person from the 60's.
Get somebodys football uniform and go as a football player
If you have any halloween costume ideas that you would like added please leave the costume idea in my guestbook and I will add it.