I am a child of the 70's. One of the traditions we have lost from that era is the pot-luck dinner. That's sad, as it was a way to gather friends without a huge expense on the host.
Now would be the perfect time and the perfect economy to bring that tradition back. A sign up list can be sent by group email. Make sure to have half of the categories per number of couples. That way you have more than one choice for each category. And the sign up sheet will guarantee that you don't end up with a table full of nothing but desserts!!
As host or hostess, sign up for the main meat dish yourself. Make it easy, you still have to greet, mingle, and make your guests feel welcome! And remember, you're not running an open bar. Pick one or two "signature" drinks and make them by the pitcher. Set them up on a table with glasses and ice. Let your guests serve themselves...remember, these are your friends...they won't mind!!
As an added bonus for your guests, consider setting up a leftover table. You can purchase small leftover containers at a local dollar store in 4-packs. Then, if your guests fall in love with a dish brought by someone else, they can take some home. Providing twenty containers will only run you $5.
While we all know that the fashion and disco are parts of the Seventies we never want to come back, this is one tradition that is worth revisiting! Let me know how your potluck goes!