craftgrrl | Fancy Dress Problem

Ok, my friend is having a 16th birthday party, with a fancy dress, on the theme of films. she goes to the school I will be going to next year, as do most of the people at this party. I want to make a good impression. I don't want to be wearing anything ridiculous or silly, or anything tacky and revealing. Just something nice. I intend to make it if possible, but with minimum effort as i havent much time. any ideas? Thanks