Sober mixers...

[ChildoftheHorn]

You could turn the different drink in every room type party sober. Then have a different activity in each room. You could also have a mini-contest mixer where you have little competitions or have the girls wear their swimming suits under their clothes and have a water-fight with a balloon toss.
Maybe a beach theme where you have someone teach Hula Dancing and have a limbo contest -remember the Lei's.
I know that these totally seem childish, but they can be really fun and more memorable than the typical mixer....


A more adult theme could be like an Arabian nights type thing where you hang cloth from the inside of the room to make it like a tent, get a bunch of cushions to sit on, a belly dance teacher, and a hookah if possible. The Hookah will totally make up for the lack of alcohol and you could keep it in a corner where it won't bother people who don't want to do it.