Before the Party:
Create a CD with theme songs from popular movies. Write down the name of each movie the corresponds with each track on the CD.
During the Party:
Play each track to your guests. Have your guests call out the name of the movie that fits the theme song as soon as they know it. The first person to call out the correct movie gets a point. Keep track of each guest's points, and at the end of the CD, award a prize to the person with the most points.
You could also divide your guests into two groups and play this game in teams.