Something like the feasts served at Father Christmas in Narnia, or Pentwyvern Harvest Feast. Back at Spring Valley, the food vendors would put on a feast of sorts where they sold tickets and served a fancier buffet meal. At Father Christmas, volunteer cooks make the feast and volunteer servants wait tables, serving appetizers, soup, a main course, and dessert. At Harvest Feast they had garb and table decorating contests with prizes.
Basically it would be a catered-somehow dinner on an opt-in basis for those who want to get fancied up and have a feasting-hall dinner with fellow Rag-goers. The dinner could be cooked by interested and proven Dagorhirrim, or a caterer could be called in (if the Coopers allow.) Ticket sales could even offer compensation to the servants that volunteer, maybe? Who knows.