Unless things have changed drastically, the day will mostly consist of lunch with your future classmates (and don't be surprised if the class is completely different in July), a question and answer session with current students, and a housing fair. I believe that the fourth years are going to try to advertise some of their stuff (furniture, etc), but I'm not sure how that's going to work.
I'm going to try and make it to the Q and A, but it depends on how guilty I feel about skipping out of Heme/Onc for a little while... luckily, I matched, and guilt is now a foreign emotion.
Paige