As much H2O as possible, and a few ibuprofen. imho there is no magical cure for a hangover.
I was about to call the OP immature and naive, however, our firm had a retreat at a fancy resort with people from all over the country and all kinds of "festivities" on a Thu. evening. Needless to say, most everyone was "useless" on Friday. I would not want to multiply everybody's daily salary by how many were in attendance, as how much the firm lost that day, OUCH!
Have you ever said no to crab cakes and roast duck breast for lunch? Most of us did!