Host a 'Tupperware Party'
If you have no idea what a Tupperware party is then first, why are you having an 80’s theme? You are clearly too young. Second, stop everything and watch this incredible*, fantastically 80’s advert to demonstrate. Yes, the Tupperware party was the humble beginning of the many pyramid schemes we know and love today. Now, I don't expect you to actually sign up to become an official host**, however, you can have a really fun fake version by asking all of your guests to bring some Tupperware from home and do a fake presentation to the group just for a laugh.
*Chips keep chipp-ier is a personal favourite.
**Yes, I sh*t you not, these parties are still a thing in some places.