Homecoming Ideas............?

So, it's only May, but homecoming is practically around the corner. I am on the committee for planing next year's homecoming dance. However, none of us have any idea where to start and none of us have good ideas for a theme. For our homecoming dance/parade/spirit week/pep rally/game, the freshmen, sophomores, juniors, and seniors all have their own "part" for the central, main theme. For example, last homecoming was "Bright Lights, Big Cities, Homecoming '10" and the freshmen had the city hollywood, sophomores had new york, juniors had hawaii, and seniors had vegas. So if someone could help me with that, it would be awesome! Thank you so much!(: