i would take out all the dresses i have and ask the girls to bring theirs aswell.. Have sort of a fashion show then i would get dressed up and go out for a night of fun.. ride around the town all dressed up, stop at random places and just laugh it up...
A great new trend is letting the girls pick their own dresses. You just pick the color and type of fabric so the girls can be comfortable in what they are wearing. No need to have them all look the same.
try making it look flapperish with sparkle or be famous people like paris, nicole richie, and lindsay lohan