[The following list has been compiled from empirical evidence gathered by the author during recent study in the field of annual vivocelebratory hosting of young adults. The information given represents informed conjecture and has yet to be statistically proven.]
1. Spirits. Like way more than you think. Let people B their own B when it comes to beer and cider and wine, but make sure you have copious gin and jäger and vodka.
2. Chocolate cake. Healthy salads are great and all but Point 1 of this extensive and exhaustive list means people will develop strong feelings about chocolate cake over the course of the evening.