With a Hollywood theme, you could play the "Who Am I" game. Put the name of someone famous on labels... Ashton Kucher, Justin Timberlake, Nemo, J Lo ... and put it on everyone's back as they enter the party. Each person can only ask "yes" or "no" questions as to who they are. For example, "Am I male?", "Am I on telelvison?", etc. Good thing to get the party started and everyone talking.
Maybe people can "dress up" as their favorite stars, or a charade type game where they act out their favorite stars (karaoke?).
That's all I have for now, will keep thinking on it.