Hollywood and/or Movies continues to be a popular choice for a costume event. 
Costumes for a James Bond event can be found here

In most respects, almost any costume can be related to some film or other (although it may depend upon how strictly you interpret 'Hollywood').
This is a selection of our movie-inspired costume characters - click on each group to get the bigger picture!  Alternatively, use the 'Decades' links on the lower half of the page to explore film characters by decade.