trick or treat

I went to the malls last Sunday and saw the adorable kids in their halloween costumes doing the trick or treat. They looked so cute! I don't remember i ever did it when i was a kid. Well, trick or treat is not that popular here. It's only during Christmas that I went from house to house. I have never tried attending a costume party either. So, I have this "dream" of attending one. Hehe! If it happens, what should my costume be like? Hmmnnn...