The first part of the party can be an ice breaker, each person has to go around the table and tell the others about themselves aswell as one thing they enjoy about their culture.
Each person can bring or wear something which represents their culture if they like and explain this.The next thing we can do is a drinking game, I have devised a game where each participant is handed a card with an aspect of culture written on it. No one knows which aspect they have until they open the peice of paper. Each person has to pick a peice of paper and then afterwards we go around the table and give examples of differences with each aspect of culture. For instance, Business negotiation is one aspect of culture, differences could be how the Chinese do business as opposed to the Western cultures. When we come to someone who can not come up with a difference within this aspect anymore, they have to drink. Its really a drinking game where people have to speak alot of english.
The last part can be a simple drinking game where everyone has to rhyme sentences in english, each person who goes has to come up with a new rhyme and once they are can not come up with one, they have to drink. This could be very fun.