Guy here - Xmas gift ideas for 18 yr old girl?

I'm going to spend the holiday with my sister and her family this year, my niece is 18 yrs old and I have no clue what to get her. My nephew is easy, an Xbox game will do the trick, but her I have no clue. Usually I just mail gift cards but since I will actually be with them (live out of state) I wan't to get her something real.

Any help? :/