George Weasley
George showed up looking put together but not exceptionally fancy - he is George, after all. He would mostly hang out alongside Fred, but did wander off every so often to talk to the founders and his friends. It is quite possible, in fact probable, that he brought mini-fireworks (like the one he and Fred were playing with in OotP) and put on a minor display in between the main course and dessert.
I'm preparing for the hurricane, so if you'd like to just say whatever your character did with George, that would be best for me! <3